Which of these variables would be at the ratio level of measurement? $($SELECT ONLY ONE ANSWER$)$

a$)$ The distances between Las Vegas, Santa Fe$,$ Albuquerque, and Las Cruces, New Mexico.

b$)$Wages based on commission only

c$)$ The height of all statistics students.

d$)$ Sally drives a BMW while Bill drives an old Ford pick$-$up$.$ Marla drives a Honda scooter and Dave drives Chrysler mini$-$van.