For each blank select one entry from the corresponding column of choices. Fill all blanks in the way that best completes the text.

Prior to taking on the new invader, the defending army had engaged in arduous combat; it is likely that the _______ resulting from waging two battles in two days played a part in its subsequent defeat.

a. Bellicosity 

b. Pugnacity 

c. Pacification 

d. Enervation 

e. Aggravation