2. A mall sells three models of electric vehicles: A, B, and C. It is known that the sales revenue of model A in the first quarter accounts for $56\%$ of the total sales revenue of these three models. In the second quarter, the sales revenue of models B and C decreased by $a\%$ compared to the first quarter, but the total sales revenue of electric vehicles in the mall increased by $12\%$ compared to the first quarter, and the sales revenue of model A increased by $23\%$. Then the value of $a$ is ( ).
(A) 8
(B) 6
(C) 3
(D) 2
2.D.

From the problem, we have
$$
(1-56 \%) (1-a \%) + 56 \% \times (1+23 \%) = 1+12 \% \text{.}
$$

Solving for \( a \) gives \( a=2 \).