Tom has a collection of 13 snakes, 4 of which are purple and 5 of which are happy. He observes that all of his happy snakes can add,
none of his purple snakes can subtract, and
all of his snakes that can't subtract also can't add.
Which of these conclusions can be drawn about Tom's snakes?

A)Purple snakes can add.
B) Purple snakes are happy.
C) Snakes that can add are purple.
D) Happy snakes are not purple.
E) Happy snakes can't subtract.