Answer:
C) reciprocity
Step-by-step explanation:
Based on the information provided within the question it can be said that this scenario is an example of reciprocity. This term refers to exchanging one thing for another in which both parties benefit in their own unique way. Which is the case since Bob buys equipment from Allied Tools which generates revenue for Allied Tools thus benefiting them, and Allied Tools hires Bob periodically which generates revenue for Bob thus benefiting him.