A factory worker packed 12 boxes at a constant rate, took a 30-minute break, and then continued packing the boxes at twice the rate before the break. The worker then spent `1/2` an hour cleaning the work area. Which of the following represents the domain for this situation?
A. 4.5≤t≤24
B. 0≤t≤4.5
C. 0
D. 0≤b≤24