Chad worked overtime this week, but he readily agreed to his supervisor's request to work for five more hours during the weekend. This is because Chad likes to cooperate with his superiors. In the context of McClelland's Learned Needs Theory, Chad is most likely motivated by the need for:

Chad id most likely motivated by the need for AFFILIATION.

Explanation:

According to McClelland's Human Motivation theory, every person has one of three main motivators:

1) the need for power

2) the need for affiliation

3) the need for achievement

Achievers like to achieve goals and solve problems. Those with a strong need for affiliation  value relationships above anything else and they don't like to stand out or take risk. Those with a strong power motivator like to control others and be in charge.

i would say b. research typically uses a variety of sources

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.