Although British and French abolitionists of the late 1700s predicted that manumission and the blockading of slave ships
would gradually undermine it, slavery continued to be the dominant cultural and economic force in southern America until the end of the American Civil War in 1865.
(A) would gradually undermine it
Correct. Since the passage conveys that a prediction of future was made in the past. So use of '
would' is justified. Also, '
Although ' starts a dependent clause , so here
it takes as its subject , the subject of the main clause that follows ,i.e slavary.
(B) to be a gradual undermining of it
Incorrect. use of '
to be' for a hypothetical situation is not correct. '
Would' should be used to refer to future in the past.
(C) would be a gradual undermining of slavery
Incorrect. According to passage '
manumission and the blockading of slave ships' will cause some action (undermine slavery), but they are not the action themselves. Thus, this choice does not convey proper meaning.
(D) to gradually undermine slavery
Incorrect. Use of '
to' for a hypothetical situation is not correct. '
Would' should be used to refer to future in the past.
(E) gradually undermining it
Incorrect. 'gradually undermining it' modifies '
manumission and the blockading of slave ships' and thus the first clause does not contain any verb which makes this choice incorrect.