Which of the following describes an agent in the context of agency law?

In the context of agency law, an agent is best defined as an individual authorized to act on behalf of another, typically referred to as the principal. This relationship allows the agent to perform tasks or make decisions that legally bind the principal to agreements and transactions. The fundamental principle of agency is that the agent has the authority to represent the principal in specific matters, which can include various activities such as negotiating contracts or making purchases.

This definition is inclusive and broadly applicable across multiple industries and roles, not limited to financial transactions or the payment process. An agent's authority can arise from a written agreement, a verbal agreement, or can even be implied through the conduct of the parties involved.

The other options focus on specific entities or roles which do not encompass the broader definition of an agent. For example, processing payments is a function that can be performed by those outside of an agency relationship, while the roles of financial institutions and licensed merchants have specific regulatory or operational criteria that do not fit the general definition of agency law. Thus, option C accurately captures the essence of what constitutes an agent in legal terms.