3. Given a set $S \subseteq\{1,2, \cdots, 26\}$, and it satisfies that the sum of any 2 elements in $S$ cannot be divisible by 5. Then the maximum number of elements in the set $S$ is ( ) .
(A) 10
(B) 11
(C) 12
(D) 13
3.C.

The number of elements in $S=\{1,2,5,6,7$, $11,12,16,17,21,22,26$ and so on that satisfy the condition is the largest.