12. A magazine prints six photos, which are of three celebrities and their baby photos, but the three baby photos are not labeled with whose they are, and readers have to choose themselves. Assuming each photo is equally likely. Then the probability that a reader randomly selects three photos, making the baby photos correspond to the names of the three celebrities is ( ).
(A) $\frac{1}{9}$
(B) $\frac{1}{6}$
(C) $\frac{1}{4}$
(D) $\frac{1}{3}$
(E) $\frac{1}{2}$
12. B.

Let event $A$ be the event of correctly selecting three baby photos. Then
$$
P(A)=\frac{1}{3!}=\frac{1}{6} .
$$