We have: \(A = \frac{1}{2} \int_{4}^{6} x \cdot (6x - x^2) \, dx.\)
Calculating the integral:\(A = \frac{1}{2} \int_{4}^{6} (6x - x^2) \, dx = \frac{76}{3}.\)
Multiplying by 12:\(12A = 12 \times \frac{76}{3} = 304.\)The Correct answer is: 304