2. (10 points) Two strips of paper, the longer one is $23 \mathrm{~cm}$, and the shorter one is $15 \mathrm{~cm}$. After cutting off the same length from both strips, the remaining longer strip should be at least twice as long as the remaining shorter strip. The minimum length that can be cut off is ( ) cm.
A. 6
B. 7
C. 8
D. 9
【Analysis】Let the length cut off be $x$ cm, then the longer remaining piece is $(23-x)$ cm, and the shorter remaining piece is $(15-x)$ cm. According to the requirement that "the longer of the two remaining strips must be at least twice the length of the shorter strip," we can set up the inequality: $23-x \geqslant 2(15-x)$, and solve this inequality.

【Solution】Solution: Let the length cut off be $x$ cm, we get:
$$
\begin{aligned}
23-x & \geqslant 2(15-x) \\
23-x & \geqslant 30-2 x \\
x & \geqslant 7 .
\end{aligned}
$$

Answer: The length cut off must be at least 7 cm.
Therefore, the correct choice is: B.