Question

Instead of select the top 3 records, I hope to select the top 3rd record in a single query.

Answer 1

Assuming your query already defines the right order in your result set, you can just skip the first two using Skip() then finally take the third result, or null if it doesn’t exist (less than 3 results):

var result = query.Skip(2).Take(1).SingleOrDefault();

Edit:
Actually this can be done shorter, since the Take(1) and SingleOrDefault() can be expressed with FirstOrDefault() instead:

var result = query.Skip(2).FirstOrDefault();