Please Help!

Read the following passage written by a teen hero:
1. I want to be a vocal advocate for nature.
2. I reject the idea that I am too young to make a difference.
3. I recently helped a group with a river cleanup.
4. I was mortified to see the destruction of animals and plants.
5. 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.
6. I believe my vocation is to help citizens see that we are at a junction.
7. We can decide to subject nature to abuse, or we can decide to be a benefactor to nature.
8. I won't let obstacles detract from my mission.

In sentence 4, the root in the word "mortified" means:

a. frustration

b. death

c. disappointment

d. sadness