Read the following passage written by a teen hero:

I want to be a vocal advocate for nature.
I reject the idea that I am too young to make a difference.
I recently helped a group with a river cleanup.
I was mortified to see the destruction of animals and plants.
When I got home, I composed a letter to my state politicians and asked them to allocate more money to the local river cleanup effort.
I believe my vocation is to help citizens see that we are at a junction.
We can decide to subject nature to abuse, or we can decide to be a benefactor to nature.
I won't let obstacles detract from my mission.


What is the meaning of the word "advocate" as it is used in sentence 1?
One who is empty of passion for the future or progress
One who goes toward joining the government
One who puts together efforts to fight progress
One who uses his or her voice in favor of something