1 : If the parachutes had failed to open
P : the whole of his couch would
Q : he could have pulled a liver to provide an emergency ejection
R : and special parachutes would have unfolded
S : then have been fired from the cabin
6 : to bring him down.

The Proper sequence should be:

A. PSRQ

B. QPSR

C. RSQP

D. SQPR

Answer: Option B

Solution(By Examveda Team)

If the parachutes had failed to open he could have pulled a liver to provide an emergency ejection the whole of his couch would then have been fired from the cabin and special parachutes would have unfolded to bring him down.