20 Points! Answer correctly for brainliest! Which of the following corrects the pronoun error in this passage?

The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made them happy.

The sixth-grade students liked volunteering his or her time to read to the elderly people in the hospital. It made them happy.
The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made the volunteers happy.
The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. They made them happy.
The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. Reading made them happy.

Which pronoun has an unclear antecedent in the following sentences?

The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made them happy.

Their
It
Them
No unclear antecedents

1. the last one

2. It

Explanation:

I did my best!

- "a.) it includes letters and books gathered over 1200 years, and consists of two parts.

- most of the new testament is letters from paul to the different churches, and since there's a new testament that means there is an old testament. "

in ray bradbury's short story "a sound of thunder", mr. eckels's fearfulness leads to drastic consequences for the rest of the world.

in the story, mr. eckels, who is a hunter, hires a time travel company to travel to the age of dinosaurs. although he is excited for the hunting expedition at the beginning, when they reach there and mr. eckels sees the tyrannosaurus, he feels frightened. as he is afraid of the tyrannosaurus, he steps off the path although he has been warned not to do it. by stepping off the path, the entire course of the future is affected: mr. eckart alters the future by stepping on a butterfly, which causes a new man to be elected president in the future. in that way, it is mr. eckart's fearfulness what triggers 'the butterfly effect' and what leads to drastic consequences for the rest of the world.