Question: Let $ S$ = $ \{<M> | TM$ $ M$ on input 3 at some point writes symbol “3” on the third cell of its tape $ \}$ . Show that $ S$ is r.e. (Turing acceptable) but not recursive (decidable).

I’m bit confused about this question, I’m not even sure how exactly should I start an approach to it. As I study from Sipser’s book, in general when we proof a language is undeciable, we use contradiction to show that if $ S$ is decidable, then by doing some trick, $ A_{TM}$ is also decidable but it’s not. Thus, $ S$ is not decidable. However, this question also asked to show $ S$ is acceptable. I’m thinking if we show that $ S$ is undecidable, it’s sufficient to see that $ S$ is acceptable?(I’m totally not sure) Any suggestion?