Ivan Is Going Bungie Jumping and He Has to Wear

Ivan is going bungie jumping and he has to wear a special harness that fits snuggly across his ribs.The problem is that his ribs are extremely ticklish,and he can't stand having the instructor buckle him up without having a tickle fit.So,he does his best to do up his own harness and the instructor inspects the finished job.Why was Ivan able to do it himself when he was too ticklish with the instructor?

A) the instructor was trying to tickle him
B) the tactile stimulation is surprising when the instructor is doing it
C) Ivan's tactile threshold is higher when the instructor is tickling him than when he tickles himself
D) Ivan is beginning to outgrow the ticklish stage, as indicated by the fact that he can no longer tickle himself