Which term refers to a type of financial service used to provide capital to a customer?

The term that refers to a type of financial service used to provide capital to a customer is "facility." A facility typically refers to a loan arrangement or credit line that a financial institution offers to customers, enabling them to access funds as needed. This could include various forms of credit, such as revolving credit facilities, term loans, or other types of financing that provide capital assistance.

In the context of banking, a facility serves as a mechanism for delivering financial resources to borrowers, allowing them greater flexibility in managing their financial needs. It encapsulates the idea of readiness to provide funds up to an agreed limit, making it a vital tool in retail banking.

The other terms listed do not adequately describe this concept. "Portfolio" refers to a collection of financial assets, "instrument" typically denotes a specific financial contract, such as stocks or bonds, and "account" usually refers to a banking or investment account where funds are stored rather than a direct means of capital provision. Thus, "facility" accurately captures the essence of a financial service aimed at providing capital to customers.