The graph shows how many calories are in different amounts of popcorn.

Which of these statements is true?

1. There are 125 calories in 2 cups of popcorn.
2. There are 50 calories per cup of popcorn.
3. The unit rate of calories in popcorn is 73.5 calories per cup.
4. There are 1.5 calories in 75 cups of popcorn.