Hello There!
Great question you asked! First, we must know what an opinion is. An opinion is a personal view or attitude of something.
Your answer would be the last one. "People must take action now to protect coral reefs by reducing pollution and emissions of noxious gases."
This is an opinion because it's stating that people must take action not all people have to take action if they choose not to.
Have A Great day!
Answer:
it is inportant so you can understadt it better
Explanatioan:
I believe the preposition in that sentence is "into".