Which of the Following Is True Regarding the Placement of the Image

Which of the following is true regarding the placement of the image receptor for an AP axial (Towne) projection of the skull?
1) Its upper margin is at the level of the top of the cranium.
2) Its upper margin is 2 inches above the top of the cranium.
3) Its upper margin is 2 inches below the top of the cranium.

A) 1 only
B) 2 only
C) 3 only
D) 1, 2, and 3