SI: There were shots as I ran. S6 : Staying submerged was only too easy with so much clothing and my army boots. P : The water was icy, but I stayed until I thought my lungs would burst. Q: I tripped at the edge and went in with a splash. R : The minute I came up I took a breath and plunged down again. S : I ducked down, pushed between two men and ran for the river. The proper sequence should be
- AS Q P R
- BP R Q S
- CS Q R P
- DQ S P R
Explanation
S1 has the narrator running as shots are fired, so S (ducking down, pushing between two men and running for the river) is the immediate continuation. Q follows with the trip at the river's edge and the splash. P describes staying submerged in icy water until the lungs nearly burst, and R has him surfacing for breath and plunging down again. S6 explains that staying submerged was easy because of his heavy clothing and army boots, which justifies the long submersion in P. Hence SQPR, i.e. option A.