Which question BEST frames new inquiry if you were working on a project about how to engineer a bridge?

Responses
A How do bridges hold the weight of all the cars and trucks they have to support?How do bridges hold the weight of all the cars and trucks they have to support?
B How have bridges affected the economic growth of certain cities?How have bridges affected the economic growth of certain cities?
C What style of bridge can hold the most weight and last the longest without repair?What style of bridge can hold the most weight and last the longest without repair?
D What kind of materials are bridges made of?What kind of materials are bridges made of?