1. If the set
$$
A=\{1,2, \cdots, 10\}, B=\{1,2,3,4\},
$$
$C$ is a subset of $A$, and $C \cap B \neq \varnothing$, then the number of such subsets $C$ is $(\quad)$.
(A) 256
(B) 959
(C) 960
(D) 961
- 1. C.

From the fact that there are $2^{6}$ subsets $C$ satisfying $C \cap B=\varnothing$, we know that there are $2^{10}-2^{6}=960$ subsets $C$ satisfying $C \cap B \neq \varnothing$.