The function $f$ has continuous second derivatives, and a critical point at (2, -7). Suppose $f_{xx}(2,-7) = -3, f_{xy}(2,-7) = 1, f_{yy}(2,-7) = 10$.
Then the point (2, -7):

A. cannot be determined
B. is a local minimum
C. is a local maximum
D. is a saddle point
E. None of the above