'His nose is as long as Pinocchio's' can be both an allusion and a simile.
An allusion is when a phrase gives an indirect reference to something.
From the given phrase, a reference to the story and image of Pinocchio is given.
A simile is when there is a comparison being made.
The given phrase compares both the person's nose and Pinocchio's nose.
Hence the right option would be (d) both choices 1 and 3 are correct.
Hope it helps. :)
