Hi
I guess the sentence is :
Les soldats commençaient leur journée tôt le matin.
soldiers were beginninng their day early in the morning.
CORRECT ANSWER = C
The tense used is IMPARFAIT
A- finissaient = were finishing
B- faisaient = were doing
C- commençaient = CORRECT ==> were begining
D- entraînaient = trained.
to be correct, it should have been =s'entraînaient (were training)
hope this helps :)