Correct option is D
Option (d) contains an error.
The error lies in “brought to an end the Reagan–Bush years.”
After the structure “will have been,” the complement should be an infinitive (to + verb) or a gerund (-ing form), not a past participle.
Therefore, instead of “brought,” we need “bringing” (gerund) or “to bring” (infinitive).
Correct sentence (Gerund form):
But perhaps Governor Clinton’s most remarkable achievement will have been bringing an end to the Reagan–Bush years.
Also acceptable (Infinitive form):
But perhaps Governor Clinton’s most remarkable achievement will have been to bring to an end the Reagan–Bush years.
Information Booster:
Use of the Infinitive after “will have been”:
His greatest contribution will have been to inspire young minds.
Their boldest move will have been to reduce the deficit.
Use of the Gerund after “will have been”:
Her biggest success will have been leading the project to completion.
Our key achievement will have been securing bipartisan support.
Note: Both gerund and infinitive complements are grammatically sound after “will have been.” The original past participle (“brought”) is incorrect in this position.