Shelly and Terrence earned points in a game by completing various tasks. Shelly completed x tasks and scored 90 points on each one. The expression below shows Terrence's total points in the game: 90x − 20

What does the constant term of the expression represent?

The total points Terrence earned
The total number of tasks Terrence completed
The sum of Shelly's and Terrence's total points
The difference between Shelly's and Terrence's total points