Geometry i need help with this

Look at this expression. a3b3c a-3b-3c-1 which of the following is the simplest form of the expression above?

Which of the following situations represents a linear relationship? a. theresa increases the distance she runs by 0.1 miles every week. b. the volume of a box depends on the length of box. c. the amount of money in a bank account increases by 1 percent each year. d. the population of a town doubles every 5 years.

Anyone know? will mark brainliest if you're correct!