已知函数<img src="https://nimg.ppkao.com/2018-09/yuanhao/2018090715304985354.jpg?sign=bc082bd9dfd18b27d39dd059414fcbde&t=62d4d132" />,则其Hessian矩阵是()。<br /> <img src="https://nimg.ppkao.com/2018-09/yuanhao/2018090715305450503.jpg?sign=81139721ddcccc3e0c797102cedf9293&t=62d4d132" />
A、A
B、B
C、C
D、D