An elevator rises steadily up a skyscraper. After 4 s it is 33 m above the ground, 2 s later it is 47 m above the ground. Which equation models its position, y, with respect to time, x?

A. y-47= -7(x-2)
B. y+33=7(x+4)
C. y-33= -7(x-4)
D. y-33=7(x-4)