[SC悬赏令] OG16-37 关于could have been的问题。拜托啦

OG16-37

Not trusting themselves to choose wiselyamong the wide array of investment opportunities on the market, stockbrokersare helping many people who turn to them to buy stocks that could be easilybought directly.

(A) stockbrokers are helping many people who turn to them to buy stocks thatcould be easily

(B) stockbrokers are helping many people who are turning to them for help inbuying stocks that they could easily have

(C) many people are turning to stockbrokers for help from them to buy stocksthat could be easily

(D) many people are turning to stockbrokers for help to buy stocks that easilycould have been

(E) many people are turning to stockbrokers for help in buying stocks thatcould easily be

这道题选E，我只有一个地方不懂，希望大家解答。

OG关于D的解释是：the tense of the verb could have been does not match the tense of the verb

earlier in the clause; the point is not that people are turning to stockbrokers

for help in buying stocks that at some earlier time could have been bought

directly, but rather that the stocks could be bought by the people directly at

the very time they are seeking help from the stockbrokers.

我不是很懂。我理解的D could have been done是虚拟语气，表示本可以很轻易的直接购买但是却像stockbroker购买。不知道为什么OG觉得这样是错的。

谢谢大家了！！！