为自己加油

A donkey may permit himself to fall under his burden, but not a human being, the best of creation.（ ）

A.
...a human being should not behave like a donkey. 
B.
...a human being should forever strive for a better life. 
C.
...a human being should not give up under harsh conditions. 
D.
...a human being should be physically stronger than a donkey.