Why Should the Foot Be Dorsiflexed to a 90-Degree Angle

Why should the foot be dorsiflexed to a 90-degree angle with the lower leg for a lateral ankle projection?
1) It places the tibiotalar joint in a neutral position.
2) It prevents the patient from rotating posteriorly.
3) It allows the anterior pretalar fat pad to be used to detect joint effusion.
4) It positions the talar domes on top of each other.

A) 1 and 3 only
B) 1, 2, and 3 only
C) 3 only
D) 1 and 4 only