Explanation:

- Business: Involves running a company or enterprise for profit. People invest capital and take risks to offer goods or services. They usually work for themselves rather than others.

- Profession: Involves specialized knowledge, often requiring qualifications and adherence to ethical standards. Examples include doctors, lawyers, and engineers.

- Employment: ?? Correct Answer: Involves working for others in exchange for remuneration. It typically involves a contract or agreement, clearly defining roles, responsibilities, and compensation.

- None of these: This is a catch-all option if none of the above fit, but it’s not applicable in this context.