There are two major problems with the original sentence: (split is much - many / pose - poses)
1. Much vs many : Debries = uncountable = much (such as so much money vs so many dollars where money is uncountable and dollars is countable )
2.Subject verb agreement: pose vs poses Much debris is a singular subject and fits with poses.
NASA recently published a report cautioning that
many of the space debris to which satellites and spacefaring vessels are exposed pose a significant risk of damaging or destroying satellites and vessels in instances of accidental impact.
A:
many of the space debris to which satellites and spacefaring vessels are exposed pose - out due to error 1
B:
many of the space debris that satellites and spacefaring vessels are exposed to
poses - out due to error 1 & 2 many - plural => pose
C:
many of the debris that is in space and that satellites and spacefaring vessels are exposed to pose - out due to error 1
D: much of the debris
that is in space and satellites and spacefaring vessels are exposed to poses -wordy construction. No need to classify derbies
E: much of the space debris to which satellites and spacefaring vessels are exposed poses - correct option.
Answer - E