Seismologists studying the earthquake

[missionGMAT007]

Seismologists studying the earthquake that struck northern California in October 1989 are still investigating some of its mysteries: the unexpected power of the seismic waves, the upward thrust that threw one man straight into the air, and the strange electromagnetic signals detected hours before the temblor.

(A) the upward thrust that threw one man straight into the air, and the strange electromagnetic signals detected hours before the temblor
(B) the upward thrust that threw one man straight into the air, and strange electromagnetic signals were detected hours before the temblor
(C) the upward thrust threw one man straight into the air, and hours before the temblor strange electromagnetic signals were detected
(D) one man was thrown straight into the air by the upward thrust, and hours before the temblor strange electromagnetic signals were detected
(E) one man who was thrown straight into the air by the upward thrust, and strange electromagnetic signals that were detected hours before the temblor

OA A

[Salman Ghaffar]

This question requires parallel construction among the three mysteries:
1. the unexpected power of the seismic waves
2. the upward thrust that threw one man straight into the air, and
3. the strange electromagnetic signals detected hours before the temblor

Only A has all the 3 items in parallel form. Hence A is the answer

[Bharat]

Answer: A
Please follow parallelism for the answer. There are three mysteries: unexpected power, upward thrust & electromagnetic waves. Extra words in the sentence are to qualify (describe) these three further.
B: EM waves appear as information rather than a mystery.
C, D: Thrust & EM waves are explained as information rather than mysteries.
E: Thrust is explained as information.

A is the only structure that follows parallel structure to list the three mysteries with appropriate descriptions.

Let me know if you have questions.
Regards,
Bharat.