4. A folk song competition is held in a certain place, with a pair of singers from each of six provinces participating in the final. Now, four winners need to be selected. The probability that exactly two of the four selected are from the same province is ).
(A) $\frac{16}{33}$
(B) $\frac{33}{128}$
(C) $\frac{32}{33}$
(D) $\frac{4}{11}$
4. A.

The probability that exactly two of the four selected contestants are from the same province is
$$
P=\frac{\mathrm{C}_{6}^{1} \mathrm{C}_{5}^{2} \times 2 \times 2}{\mathrm{C}_{12}^{4}}=\frac{16}{33} .
$$