Only “safe” option I would say is not to do anything =)
Street fighter is generally rock, paper scissors, especially after knockdown. I havent had time to play SF V much, so im not sure about priorities, invincible frames etc.
But meaties should be pretty safe, but then you probably need hard knockdown.
General tips, would be to either jump and cross up (if you have the right range). Low normals (preferably a combo string that starts with low and can be confirmed into a special). Overhead. Meaty. Throw. Or just do nothing and try to punish that wake up DP =)
You can also youtube Gootecks, he has a pretty good tutorial which is very basic but he explains the whole rock, scissor papers thing very good =)