Step-by-step Solution:

The difference between two sets {1, 2, 3} and {1, 2, 5} is: \[\] The difference of two sets (A - B) is defined as the set of elements that are in (A) but not in (B).\[\] Here, (A) = 1, 2, 3 and (B) = 1, 2, 5. \[\] We calculate the difference as follows: \[\] A - B = x mid x in A and x \(\notin\) B = 3 \[\] \[\] \[\] Correct Option: (c)