Let f(x, y, z)=4zz- 3yz and let P be the point in the domain of f at (3, 2, 1). A. If we are starting at the point P and we begin to move in the direction towards the point (2, 4,3), then what will be the instantaneous rate of change of the function as we begin to move in that direction? B. If we are starting at the point P, and we are allowed to move in any direction, what is the maximum possible instantaneous rate of change? C. In what direction should we move-to-achieve the maximum possible rate of change? (Give your answer as a unit vector.)