Final answer:
For an AP oblique projection of the foot, the plantar surface is rotated medially to form a 30-degree angle with the IR. However, the options in the question appear to relate to projectile motion, suggesting a possible error in the question.
Step-by-step explanation:
For an AP oblique projection of the foot, where the focus is to prominently display the structures on the lateral side of the foot, the foot should be rotated medially. During this rotation, the plantar surface should be positioned to form an angle of 30 degrees with the image receptor (IR). This positioning ensures an optimal view for diagnostic purposes. Note that the options provided in the question don't include 30 degrees, so it seems there may have been a typo or misunderstanding in the question as presented. The provided multiple-choice answers are more related to projectile motion, which is a topic in Physics.