From the last paragraph, we learn that envy sometimes stems from ______.

A．Happiness often goes hand in hand with pain.
B．One must know how to attain happiness.
C．It is important to make commitments.
D．It is pain that leads to happiness.

A．have as much fun as possible during one's lifetime
B．make every effort to liberate oneself from pain
C．put up with pain under all circumstances
D．be able to distinguish happiness from fun