What is the difference between a metaphor and a simile?

A)There is no difference between the two

B)A simile compares two unlike things directly by saying or implying that one thing is another while a metaphor compares them indirectly by saying or implying that one thing is similar to another.

C) A metaphor compares two unlike things directly by saying or implying that one thing is another while a simile compares them indirectly by saying or implying that one thing is similar to another.