Answer
a) Tarzan’s acceleration is towards the point where the vine connects to a branch.
b) Tarzan’s acceleration is directly upwards.
Work Step by Step
Assuming the vine Tarzan is swinging from is held taught the entire time, from the moment he steps off the branch, Tarzan begins traveling in a circular arc. Anything traveling in a circular motion is accelerating towards the point in the center of that circular arc, which is the point at the top of the vine where it attaches to something. At the bottom of the swing, this is directly above him.