IMO ans is E.
(A)stockbrokers are helping many people who turn to them to buy stocks that could be easily---incorrect, 'stockbrokers' not trusting themselves doesn't make any sense
(B)stockbrokers are helping many people who are turning to them for help in buying stocks that they could easily have---incorrect, same as A
(C) many people are turning to stockbrokersfor help from them to buy stocks that could be easily---incorrect, 'for help from them' is awkward
(D) many people are turning
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(A)stockbrokers are helping many people who turn to them to buy stocks that could be easily---incorrect, 'stockbrokers' not trusting themselves doesn't make any sense
(B)stockbrokers are helping many people who are turning to them for help in buying stocks that they could easily have---incorrect, same as A
(C) many people are turning to stockbrokersfor help from them to buy stocks that could be easily---incorrect, 'for help from them' is awkward
(D) many people are turning
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