There is lot of issues in this sentence.
Quote:
The spraying of pesticides can be carefully planned, but accidents, weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had anticipated.
(A) weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had
(B) weather conditions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than
(C) unforeseeable weather conditions, and pilot errors are the cause of much larger deposits of spray than they had
(D) weather conditions that [color=#ff0000]are not foreseeable[/color], and pilot errors often cause much larger deposits of spray than
(E) unforeseeable weather conditions, and pilot errors often cause much larger deposits of spray than they had
I think from the intended meaning of the sentence we can infer that
Quote:
Accidents, unforeseeable weather conditions, and pilot errors is a lot that causes X
.
Issues:
They do not have any antecedent, and
had is not required as there is no item in the sentence with a timeline of "very past (had)" then"past (past tense)" in terms of intended meaning.
Also in "
D" the 2nd item
weather conditions that are not foreseeable[/color] is not grammatically/structurally parallel with other item which are noun or noun phrases, as the said item is a clause with subject (weather) and (are)verb.
Hence B