Answer:
B. accustomed to it
Step-by-step explanation:
According to the given excerpt, 'habituated' means being accustomed to it.
In the short story "The Little Regiment" Billie and Dan are the two brothers. Both the brothers represent the society during the American Civil War when the family members were on the verge of fighting among themselves. Both the brothers were concerned for each other but at the same time, they were hostile too. Although they had a lot of differences of thoughts and mindsets, still they loved each other.