4. In a math competition, 57 students wore blue shirts, and another 75 students wore yellow shirts. These 132 people were divided into 66 pairs, among which 23 pairs were both wearing blue shirts. Then, there are ( ) pairs both wearing yellow shirts.
(A) 23
(B) 32
(C) 37
(D) 41
(E) 64
4. B.
$$
66-23-(57-23 \times 2)=32 \text {. }
$$