"If p then q" is same as "$p \rightarrow q"$; which is same as "p only if q".
Given: I stay only if you go
This is of the form "p only if q" which means $p \rightarrow q$
Se we can paraphrase it as "If I stay then you go"
Clearly, p = I stay.
q = you go.
Converse would be $q \rightarrow p$
which is "If you go then I stay"
Option A
From Kenneth H Rosen