Final answer:
The equation that determines the cost in dollars to clean r rooms is d = 29r.
Step-by-step explanation:
The equation that determines the cost in dollars to clean r rooms is d = 29r. Option C is the correct choice.
Let's break down the equation to understand it better. The coefficient 29 represents the cost per room. So, for each room that is cleaned, the cost would be 29 dollars. By multiplying this cost per room by the number of rooms r, we get the total cost in dollars to clean r rooms. Hence, the equation is d = 29r.