A, Life is like a box of chocolates, would be a simile. A good way to remember this is know that similes always include the word "like" or "as".
B, Maybe Forrest Gump had it right about life, would be an allusion. An allusion is like making a reference to something that a lot of people know about.
C, The world is just waiting for you to go enjoy it, would be a personification. A personification is when you give emotion or some other human attribute to an inanimate object.