got balls ?? SOLVE this simple puzzle

Many hundreds of years ago in a small Italian town, a merchant had the misfortune of owing a large sum of money to the moneylender. The moneylender, who was old and ugly, fancied the merchant's beautiful daughter so he proposed a bargain. He said he would forgo the merchant's debt if he could marry the daughter. Both the merchant and his daughter were horrified by the proposal.

The moneylender told them that he would put a black pebble and a white pebble into an empty bag. The girl would then have to pick one pebble from the bag. If she picked the black pebble, she would become the moneylender's wife and her father's debt would be forgiven. If she picked the white pebble she need not marry him and her father's debt would still be forgiven. But if she refused to pick a pebble, her father would be thrown into jail.

They were standing on a pebble strewn path in the merchant's garden. As they talked, the moneylender bent over to pick up two pebbles. As he picked them up, the sharp-eyed girl noticed that he had picked up two black pebbles and put them into the bag. He then asked the girl to pick her pebble from the bag.

What would you have done if you were the girl? If you had to advise her, what would you have told her? Careful analysis would produce three possibilities:

1. The girl should refuse to take a pebble.
2. The girl should show that there were two black pebbles in the bag and expose the moneylender as a cheat.
3. The girl should pick a black pebble and sacrifice herself in order to save her father from his debt and imprisonment.

Solve & mail me the answer.
Hint: The girl does nothing from the above 3 given options. But then too she saves her father of the debt AND also saves herself out of the marriage trap.