Correct Answer: B
Explanation:
The words, ‘imperatives’ and ‘exigency’ mean the same as ‘urgency’. The missing word cannot carry the same meaning as urgency as is evident from the structure of the given sentence. Therefore, A and C are clearly incorrect. Out of the remaining answer options, B and D carry the same meaning and placing either of them in the blank will render the same meaning to the given sentence. Therefore, B and D are the correct answers.