Question:
Pilots who do not have over 5,000 hours of flying experience makes it unlikely for them to be chosen as flight commanders for transatlantic flights.
Let us run through every option and decide which one works the best.
(A) Pilots who do not have over 5,000 hours of flying experience
makes it unlikely for them
The subject in this sentence is 'pilots', which is plural. The verb 'makes' does not agree with the plural subject. This reason is sufficient to dump this option right off the bat. When one thinks about the intended meaning of the sentence, it is the lack of experience that makes it unlikely for certain pilots to be chosen as flight commanders and not the pilots themselves. Even if the subject-verb agreement were to be correct, the sentence would not make a lot of sense.
Eliminate (A).(B) Pilots who do not have over 5,000 hours of flying experience are unlikely
The plural form of 'be'('are') agrees with the plural subject 'pilots'. The noun phrase 'who do not have over 5,000 hours of flying experience' correctly modifies the pilots. The sentence conveys the intended meaning without any issues.
Keep (B). (C) Not having over 5,000 hours of flying experience makes it unlikely for pilots
The sentence does not seem to have any blatant grammatical errors but the intended meaning does not seem to be conveyed properly. Do all pilots lack the experience of flying over 5,000 hours? Are all pilots unlikely to be chosen as flight commanders or only those who lack the experience? This ambiguity is resolved properly in option (B).
Eliminate (C).(D) Not having over 5,000 hours of flying experience, pilots are unlikely to
Like option (C), option (D) presents the same ambiguity. This sentence seems to convey that all pilots lack the experience of flying over 5,000 hours.
Eliminate (D).(E) Pilots not having over 5,000 hours of flying experience makes it unlikely for them
Like option (A), option (E) has the errors of incorrect subject-verb agreement and distorted meaning.
Eliminate (E).Option (B) is the best option.