MongoDB - insert single works fine, but array does not

Question

When I insert a single instance of my serializable class Answer, insert works fine. When I try to insert an array of Answers, I get an exception. Surely I don't need to cast my array of Answers to an array of BsonDocuments, do I? (I didn't need to do so for a single insert!)

/********* DOES NOT WORK - THROWS EXCEPTION *****************/

public bool addAnswers(AnswerDataModel[] answers)
    {
        bool returnval = true;

        try
        {
            this.answerCollection.Insert(answers, WriteConcern.Acknowledged);
        }
        catch (Exception ex)
        {
            LoggerModel.Log(String.Empty, DateTime.UtcNow, (int)LogSeverity.Severity.Critical, ex.Message + Environment.NewLine + ex.StackTrace);
            returnval = false;
        }

        return returnval;

    }

    /******** WORKS ********/
    public bool addAnswer(AnswerDataModel answer)
    {
        bool returnval = true;

        try
        {
            this.answerCollection.Insert(answer, WriteConcern.Acknowledged);
        }
        catch (Exception ex)
        {
            LoggerModel.Log(String.Empty, DateTime.UtcNow, (int)LogSeverity.Severity.Critical, ex.Message + Environment.NewLine + ex.StackTrace);
            returnval = false;
        }

        return returnval;

    }

And error:

Exception details:
Serializer ArraySerializer<AnswerDataModel> expected serialization options of type ArraySerializationOptions, not DocumentSerializationOptions.
  at MongoDB.Bson.Serialization.Serializers.BsonBaseSerializer.EnsureSerializationOptions[TSerializationOptions](IBsonSerializationOptions options) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Bson\Serialization\Serializers\BsonBaseSerializer.cs:line 147
  at MongoDB.Bson.Serialization.Serializers.EnumerableSerializerBase`1.Serialize(BsonWriter bsonWriter, Type nominalType, Object value, IBsonSerializationOptions options) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Bson\Serialization\Serializers\EnumerableSerializerBase.cs:line 369
  at MongoDB.Driver.Internal.MongoInsertMessage.AddRequest(BsonBuffer buffer, InsertRequest request) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\Communication\Messages\MongoInsertMessage.cs:line 149
  at MongoDB.Driver.Internal.MongoInsertMessage.WriteBodyTo(BsonBuffer buffer) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\Communication\Messages\MongoInsertMessage.cs:line 91
  at MongoDB.Driver.Internal.MongoRequestMessage.WriteTo(BsonBuffer buffer) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\Communication\Messages\MongoRequestMessage.cs:line 66
  at MongoDB.Driver.Operations.InsertOpcodeOperation.Execute(MongoConnection connection) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\Operations\InsertOpcodeOperation.cs:line 83
  at MongoDB.Driver.MongoCollection.InsertBatch(Type nominalType, IEnumerable documents, MongoInsertOptions options) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\MongoCollection.cs:line 1545
  at MongoDB.Driver.MongoCollection.Insert(Type nominalType, Object document, MongoInsertOptions options) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\MongoCollection.cs:line 1396
  at MongoDB.Driver.MongoCollection.Insert(Type nominalType, Object document, WriteConcern writeConcern) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\MongoCollection.cs:line 1410
  at MongoDB.Driver.MongoCollection.Insert[TNominalType](TNominalType document, WriteConcern writeConcern) in d:\jenkins\workspace\mongo-csharp-driver-1.x-build\MongoDB.Driver\MongoCollection.cs:line 1368

Answer 1

Insert is for inserting a single document to a collection. Use InsertBatch to insert multiple docs:

this.answerCollection.InsertBatch(answers, WriteConcern.Acknowledged);