Tigers the only guy who could beat Robinson but I still pick Robbie by a close decision. Carter and Hank give Robbie great fits, but would get outboxed in the end, resulting in more one-sided decisions. Benton loses by a wide margin just cuz he's so defensive. But Ray never hurts Benton.
I'll go with the consensus here and go with Robinson, if he's close to prime, in shape, and focused, would white wash all four of those fighters, with the toughest being Tiger because his style gave Robinson fits even in his prime. But Robinson still would beat him.