Read the sentence. the astronomy club placed the telescope on the tripod and that was their choice. according to the elements of style, which sentence is the best revision? it was chosen by the astronomy club to place the telescope on the tripod. the astronomy club chose to place the telescope on the tripod. placing the telescope on the tripod was chosen by the astronomy club. no change

The best revision is the following one: "The astronomy club chose to place the telescope on the tripod". By selecting "to choose" as the main verb, you can avoid using the coordination in the example (and that was their choice). What is more, there is no point in using the passive voice as in B and D because the agent, the doer of the action, is recovered by the by phrase (by the astronomy club).  It would be grammatically incorrect to say the following:

*Placing the telescope on the tripod was chosen

You clearly need to recover the doer of the action.  With passive constructions, this is not strictly necessary because the action performed is more important than the person doing it. That is why the agent is suppressed.  As this sentence is not the case, the passive construction is not the best revision.  

the answer a: perseverance !