Impossible to tell. Probably a forgery. Maybe not. It's a triangle and some zig-zags written with a thick marker. A 5 year old could learn to forge that.
With Trump, stick to his early, pre-campaign full name autographs. Buy inscriptions.
I would stick to earlier full signatures. In my opinion, many of the abbreviated campaign trail autographs cannot be reliably authenticated.
Full Donald Trump autographs on photos are uncommon. In my opinion, most pre-presidential signed photos are secretary. There were at least a few secretaries in play. Your best bet is with a book.