The Scorpion by Aesop

This is a parable about an old man who used to meditate each day by the river near his home. One morning he saw a scorpion floating on the water.

When the scorpion drifted near the old man, he reached to rescue it but was stung by the scorpion. A bit later he tried again and was stung again, the bite swelling his hand painfully and giving him much pain.

A young man passing by saw what was happening to the old man and yelled at him,
“Hey, you foolish old man, what’s wrong with you?
Only a fool would risk his life for sake of an ugly, evil creature.
Don’t you know you could kill yourself trying to save that ungrateful scorpion?”

The old man turned around and calmly replied,
“My young man, just because it is in the scorpion’s nature to sting, does not change my nature to save.”

Questions:
What is the tone of the young man? A)appreciative B)frustrated C)pastoral D)excited
What is the tone of the old man? A)quiescent B)annoyed C)happy D)fatigue
Which sentence tells the moral, or lesson of the story? What does that mean?