Which of the following is a discrete random variable? Question 16 options: a) religious affiliation of the students at a large university b) the number of customers arriving at the check-out counter of a grocery store between 5:00 P.M. and 6:00 P.M. on weekdays c) the volume of soda dispensed into 20-oz bottles by a filling machine d) the number of miles of tread life for a particular brand of automobile tires