31.
What is the purpose of the OfType operator in LINQ?

33.
In LINQ, what does the DistinctBy operator do?

34.
What is the purpose of the DefaultIfEmpty operator in LINQ?

36.
In LINQ, what does the SingleOrDefault operator do?

37.
What is the purpose of the AsQueryable operator in LINQ?

39.
In LINQ, what does the LastOrDefault operator do?

40.
What is the purpose of the Except operator in LINQ?