I've Got a Headache This Big

i had a bad headache saturday morning, and i was looking forward to my first cup of coffee when i remembered a commercial from the 80s that started out with these words: "i've got a headache this big." i found it online and recorded my own version here: do you remember what product the original commercial was for?
a) tylenol
b) metamucil
c) excedrin
double punches for everyone who knows (or tries)! the answer to thursday's trivia is: grapes of wrath