Select the real-world problem that could be solved using a proportion. A: sheila must pay $240 for a phone and then $60 each month for service. how much will she have paid after 8 months?.

B: Sheila has 2 dogs and adopts 1 more. how many dogs dose she have in total?.

C: sheila has 4 pens and 8 pencils. how many more pens dose she need to make the number of pens and pencils she had equivalent?.

D: sheila travels 240 miles in 4 hours. at this rate, how far will she travel in 8 hours?.