Answer:
C. reciprocity norm.
Step-by-step explanation:
The norm of reciprocity -
It is the method by which the kindness offered to a person is repaid back in another way , is known as the norm of reciprocity or reciprocity norm .
This norm or favor is simple as by helping others people , the people will also help you in a way or other .
It helps in the idea of helping others so as to have a healthy and happy society .
This idea is somewhere related to gratitude , mutual goodwill ,or the golden rule .
same , scenario is showcased in the question ,where Mr. walter tries to help his neighbor back , as they helped him to paint the house .
hence , the correct term for the given case is C. reciprocity norm .