If $\int \frac{3ax}{b^2 + c^2x^2} \, dx = A \log \left|b^2 + c^2x^2\right| + K$, then the value of A is (A) $3a$ (B) $\frac{3a}{2b^2}$ (C) $\frac{3a}{b^2c^2}$ (D) $\frac{3a}{2c^2}$