Fetching the document from mongodb by passing the parameters

I need to check the document exixts in the mongodb based on combination of 3 parameters.

this is the query worked on mongo db command prompt:

db.FrequencyQuestionForm.find({"data.formList.Identificatio

nDetails.Study_Id":"1"},{"data.formList.IdentificationDetails.Visit_No":"1"}).li

mit(1)

I want to use this query in entity framework.

[HttpGet]

public object getFrequencyQuestionData()

{

var connectionString = "mongodb://localhost:27017";

MongoClient client = new MongoClient(connectionString);

MongoServer server = client.GetServer();

MongoDatabase db = server.GetDatabase("FormDataBase");

MongoCollection collection = db.GetCollection("FrequencyQuestionForm");

// Here i want to call that query ..

MongoCursor cursor = collection.FindAllAs();

var count = collection.Count();

string document = cursor.ToJson();

JToken token = JToken.Parse(document);

var jObject = JObject.FromObject(new { formdata = token, count });

return jObject;

}