设 f(x) 在 [0, a] (a > 0) 上有二阶连续导数，且 f(0) = f'(0) = 0，f''(x) 严格单调递增，则A. 4int_(0)^a xf(x) , dx B. 4int_(0)^a xf(x) , dx > 3aint_(0)^a f(x) , dxC. 3int_(0)^a xf(x) , dx > 4aint_(0)^a f(x) , dxD. 3int_(0)^a xf(x) , dx

设 $f(x)$ 在 $[0, a]$ ($a > 0$) 上有二阶连续导数，且 $f(0) = f'(0) = 0$，$f''(x)$ 严格单调递增，则

A. $4\int_{0}^{a} xf(x) \, dx < 3a\int_{0}^{a} f(x) \, dx$

B. $4\int_{0}^{a} xf(x) \, dx > 3a\int_{0}^{a} f(x) \, dx$

C. $3\int_{0}^{a} xf(x) \, dx > 4a\int_{0}^{a} f(x) \, dx$

D. $3\int_{0}^{a} xf(x) \, dx < 4a\int_{0}^{a} f(x) \, dx$