Official Solution:According to Alistair Maclean’s novel, the invincible mountainous terrain of Navarone in the Aegean sea was of utmost military importance to the Germans throughout the Second World war, because they realized that, if they did not exploit its strategic location, their survival against the indomitable naval might of the British was always in peril.A. if they did not exploit its strategic location, their survival against the indomitable naval might of the British was always in peril
B. if they did not exploit its strategic location, their survival against the indomitable naval might of the British could be liable to be in peril
C. if they did not exploit its strategic location, their survival against the indomitable naval might of the British would be always in peril
D. if they were not to exploit its strategic location, their survival against the indomitable naval might of the British was always in peril
E. their survival against the indomitable naval might of the British was always in peril, should they fail to exploit its strategic location
A. The verb of the main clause is simple past. To express a future event with respect to the simple past, conditional “would” is used. Therefore instead of the verb “was”, “would be” must be used.
To explain more elaborately, consider the following sentence in simple present:
Correct: They realize that if they do not exploit, their survival will be in peril. (particular case in future: IF simple present, THEN simple future).
Wrong: They realize that if they do not exploit, their survival is in peril.
Now shift the all the verbs backward in time:
Correct: They realized that if they did not exploit, their survival would be in peril.
Wrong: They realized that if they did not exploit, their survival was in peril.
B. “Could be” and “liable to” are redundant. Conditional “would” is required as explained in A above.
C. CORRECT. Conditional “would” is correctly used to depict a future with respect to the past.
D. Correct subjunctive is “were they not to exploit" and not "if they were not to". Secondly, this is no hypothetical wish; so not an apt choice for subjunctive use. Conditional “would” is required as explained in A above.
E. 'Should’ is used in the place of 'if'. Normally such usage denotes some future happening. Hence, the main clause cannot be in the past tense, logically. Moreover, generally in GMAT “If” is preferred to “should” to express conditions.
Answer: C