Answer: C. best fits the word problem.
Step-by-step explanation:
The reason C. best fits is because the bare minimum $20 she has to pay plus .10 times whatever amount of minute's she spends talking has to equal $100 for her to stay in budget. A good example would be say she spends 800 minutes in total on her phone. 0.10 times 800 is 80. So in this hypothetical situation, it would be 20 + 80 = 100.