、。
Play or study — that's a choice you have to make.
Literal
Play or study or, choice [topic-は] you [subject-が] do-[explanatory-ことだ].
The paired か...か structure ('or') offers an alternative between two options — 'either play or study.' 選択はあなたがすることだ literally says 'the choice is the thing that you do' — an emphatic assertion of personal responsibility. The construction [clause]-ことだ can also function as strong advice or a stated principle.