You are making the same mistake, I made when I first saw this question.
About the source - it is from ofline training, which contained questions from OG, Manhattan, Kaplan and, maybe, something else, so I can not tell the original source, sorry. But the answer providied is correct.
During the summer of 1988, the reason for virtually every unusual wether condition, from droughts and heat waves to floods and storms,was said to be caused by El Nino
(A) said to be caused by - yes, too wordy, but
...
About the source - it is from ofline training, which contained questions from OG, Manhattan, Kaplan and, maybe, something else, so I can not tell the original source, sorry. But the answer providied is correct.
During the summer of 1988, the reason for virtually every unusual wether condition, from droughts and heat waves to floods and storms,was said to be caused by El Nino
(A) said to be caused by - yes, too wordy, but
...
