Which kind of power can influence behavior through personal relationships?

Relational power is the correct answer as it specifically refers to the ability to influence others through the strength and nature of personal relationships. This type of power is derived from the connections, trust, and rapport that an individual has with others, enabling them to persuade or motivate through their established social ties. When someone has relational power, they are able to leverage their network and personal interactions to create influence, making it easier to guide behaviors and decisions among peers or subordinates.

The other options highlight alternative forms of influence. Coercive power relies on the ability to impose penalties or consequences, rather than fostering cooperation through relationships. Resource control involves influence derived from managing valuable resources, which can create dependence but does not inherently rely on personal relationships. Reward power is based on the ability to provide positive reinforcement or rewards, but while this can motivate behavior, it does not depend on the interpersonal trust that characterizes relational power.