HELP ME PLEASE BRAINLIEST ANSWER PLEASE What do proportional and non-proportional real world problems have in common?

A.)they both have a y-intercept that goes through zero
B.)they both have y intercepts that are not zero
C.)they both have a unit rate or slope
D.)they both are curved lines

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

Divide the following fractions 3/4 ÷ 2/3 1/2 8/9 9/8 2

Ineed me i stuck and i don’t want to get it wrong