Astressed statistics student wants an escape from studying, but he cannot decide which entertainment product or activity to purchase. what component of motivation is lacking?

There are three components of motivation. These are activation, persistence, and intensity.

Activation is the decision to initiate a behavior.
Persistence is the continued effort towards reaching a goal despite of the obstacles he/she is encountering.
Intensity is the concentration and vigor one applies in pursuit of his/her goal.

In the above scenario, I see the presence of activation and intensity. The lacking component is the persistence. He has not yet overcome the obstacle of finalizing which activity he will pursue in escaping his stressful situation.