Although it shouldn’t have happened, on a dive i fail to watch my spg and run out of air. if my buddy is close by, my best option is to another option is to if i’m in shallow water and the surface is closer than my buddy. a) ascend using my buddy's alternate air source / make a controlled emergency swimming ascent
b) ascend using my buddy's alternate air source / make an buoyant emergency ascent
c) make a normal ascent / ascend using my buddy's alternate air source
d) make a controlled emergency swimming ascent / make a normal ascent

Complete Question:

Although it shouldn't have happened, on a dive I fail to watch my SPG and run out of air. If my buddy is close by, my best option is to . Another option is to , if I'm in shallow water and the surface is closer than my buddy.

NB: The options still remain as written in the question

a) ascend using my buddy's alternate air source / make a controlled emergency swimming ascent

Explanation:

Since I have exhausted my own air source, my buddy's alternate air source will be the only saver if he is close by. Controlled emergency swimming accent is used if the swimmer's buddy is far but the swimmer is close to the surface. Buoyant emergency ascent can only be used if the swimmer is deep away from the surface and needs to make it to the surface.

not too sure thinking all accelerations are pointed down