Which underlined gerund functions as the object of a preposition?

the legal limit for the drivers who can drive after consuming any amount of alcohol is 21 years.

explanation:

on november 1, 1996, a "zero tolerance law" was put into effect in the new york state.

according to this zero tolerance law, for people under the age of 21 years, it was illegal to purchase and possess alcohol or to drive after consuming any amount of it.

also, the alcohol involvement rate for the drivers under the age of 21 was roughly twice that of elderly drivers.

in a place once known as north america, now known as panem, is a very rich city surrounded by twelve districts. every year because this very rich city, known as the capitol, is so rich and likes to think they control all the districts - which they do - there is something known as the hunger games! this is where two children, one boy and one girl from each district from the ages of twelve to eighteen, have to leave their families and compete in the hunger games, a live event that is aired on tv's all over panem. when katniss everdeen, aged sixteen from district 12, has to volunteer to take the place of her twelve-year-old sister prim after prim's name is called forth to become the 23rd member to compete in the 74th hunger games, she promises to prim that she will win! katniss doesn't believe she's coming out alive - but she's not going down without a fight.

because district 12 is so poor, katniss has been close to death many times from starvation but she's made it through it. but this is a different kind of close to death; this katniss doesn't know if she can survive.

she doesn't want to hurt, or kill anyone but when it comes down to it katniss' instinct is to survive. but when she starts to have confusing feelings about the boy from her district who is also her fellow contender, things get worse, and then she teams up with the girl from district 11 and only one person can survive. but who will it be? will her feelings get the better of her? will she let someone else win so they don't have to die? if katniss is going to win she's going to have to be brutal. she's going to have to kill!