2. Among 5 products, there are 4 genuine items and 1 defective item. If two items are randomly selected, let the number of genuine items among them be the random variable $\xi$. Then the mathematical expectation $E \xi$ is ( ).
(A) $\frac{6}{5}$
(B) $\frac{7}{5}$
(C) $\frac{8}{5}$
(D) $\frac{9}{5}$
2. C.

The mathematical expectation is $1 \times \frac{\mathrm{C}_{4}^{1}}{\mathrm{C}_{5}^{2}}+2 \times \frac{\mathrm{C}_{4}^{2}}{\mathrm{C}_{5}^{2}}=\frac{8}{5}$.