In the given question, a statement divided into different segments is given. The first segment is fixed, rearrange the other segments to form a coherent statement. It was hard for the Afghans/ leading to the subtle plummeting of the morale (P)/ to withstand the wave after wave of enemy attacks (Q)/ their plight further worsened the situation (R)/ and the indifference of the allies towards (S)

Clearly, only segment Q fits after the first segment. This eliminates all the options except 1.

Option 2: It is incorrect because it ends in S which ends in 'towards' which can't be used to any statement.

Option 3: It is incorrect for the same reason as option 2.

Option 4: 'towards their plight further worsened' makes no sense; hence it can be eliminated.

Option 5: R is a clear misfit after the first segment; hence it can also be eliminated. Hence, the correct sequence is QSRP.