If y = 2 + 3x1 + 5x2 8x3, then controlling for x2 and x3, the

If ˆy = 2 + 3x1 + 5x2 − 8x3, then controlling for x2 and x3, the predicted mean change in y when x1 is increased from 10 to 20 equals

(a) 3,

(b) 30,

(c) 0.3,

(d) cannot be given—depends on specific values of x2 and x3.