This derivation can use all the rules of SD and SD+.

Derive: A⊃E
2. A

Given that we want to derive E, but this metavariable doesn't appear in the premises, I'm assuming we're going to use disjunction introduction to introduce it. However, the things I've tried to far have led to a dead end. I don't want someone to post the solution, but can you give me the first couple steps to get me started? Thanks!