Which scenarios represent one quantity changing at a constant rate per unit interval relative to the other quantity? Select all that apply.
A An employee earns $14 per hour.
B. An employee earns a 3% raise each year.
C. A gym charges a $50 down payment plus $30 per month.
D
A piece of gym equipment decreases 8% in value every 6 months.
E
A trainer charges $20 for every 30 minutes of training plus a $5 tip