Solution: solution: according to the meaning of the question, the focus of the parabola is on the positive semi-axis of the y axis.

Let the standard equation of parabola be x2 = 2py (P > 0),

∵ The directrix equation of parabola is y=-4,

∴-

p

2

=-4,

∴p=8，

The standard equation of parabola is: x2= 16y.

So choose: a.