C. The cat is lazy.
Explanation:
Pay attention to this part of the passage:
. . .when there was work to be done the cat could never be found. She would vanish for hours on end, and then reappear at meal-times . . .
From these sentences, the Cat seems to avoid having any responsibilities. Rather than helping others during working hours , she chose to went away and let the other works on her behalf.
But, despite having no contribution at all to the group, she stills come back during meal hours. This mean she still getting as much resources as those other members who actually made an effort.