Wittybrains Software Technologies Senior Software Engineer interview questions

Telephonic round for asp.net .... one on how to implement the singleton class and modifier to access it ... all the way from creating constructor and another on database layer which was straightforward to answer but the way to ask was complex which I found...he talked about how to access mongodb or Oracle db to be accessed without using the provider .. basically it had to do with data source control which is linq however his way of asking made me think as he talked of mongo db which I have never been asked to work on ...linq cud have been used but it is termed as data source control I was not familiar with..I read it later.. So I don't know if it was easy or difficult to answer but the interview appeared to me were tough if I talk about the telephonic interviews i have appeared for... Interviewer was bit rude