Answer:
A. The work was tedious, but we had to soldier on to meet the
deadline.
Step-by-step explanation:
Connotation means when a word has an implied meaning as opposed to its literal meaning.
Therefore, the word 'soldier' is used connotatively in option A to show that although the work was difficult, they had to "soldier on" which means they had to keep working in order to meet the deadline. This is quite different from the literal meaning of the word 'soldier' which is a member of the armed forces.