Which of the Following Arguments Commits the Fallacy of Appeal

Which of the following arguments commits the fallacy of appeal to authority?

A) Ada's throat is sore.I know because she told me so.
B) This bridge should be strong enough to take the weight of both trucks at the same time, since a Harvard professor of history says so.
C) Uncle Rick only has another six months to live, since his doctor says so.
D) I can hit the ball further if I grip my club more tightly, since my golfing instructor says so.
E) My great-great grandmother had five children, since my grandmother says so.