Who is they?
Blockbuster increased the time allotted for customers to return videos, so they would not be able to rent videos out quicker now.

A:
customers

Who is they?
The Union defeated the Confederates in the Civil war since they had better resources and numbers.

A:
The Union

Who is they?
Stark Industries produces the best technology for the military because they have a number of brilliant scientists.

A:

Stark Industries