A.When it was looking for food.B.When it saved the ant’……

There was once an ant that was very thirsty.It ran here and there looking for some water but could not find any.Then suddenly，when the ant was almost ready to die of thirst，a large drop of water fell on it.The ant drank the water，which saved its life.The water was actually a tear from a young girl who was crying.Because of her sadness，the tear had magical qualities and suddenly the ant could speak the language of human beings.The ant looked up and saw the young girl sitting in front of a huge pile of seeds.“Why are you sad？”asked the ant.
“I′m the prisoner of the giant，”the girl told the ant.“He won′t let me go until I′ve made three separate heaps of grain，barley（大麦）and rye（黑麦）out of this huge pile of seeds in which they are all mixed together.”
“That will take you a month!”the ant said，looking at the huge pile of seeds.
“I know，”the girl cried，“and if I haven’t finished by tomorrow，the giant will eat me for his supper!”
“Don′t cry，”the ant said，“my friends and I will help you.”
Soon thousands of ants were at work，separating the three kinds of seeds.
The next morning，when the giant saw that the work had been done，he let the girl go.
Thus it was one of her tears that saved her life.

A.When it was looking for food.
B.When it saved the ant’s life.
C.When it was nearly dying.
D.When it looked up.