Regulators are stakeholders who define, monitor, or enforce rules, standards, legislation, and compliance obligations that affect an organisation. In business analysis, regulators may influence what changes are possible, acceptable, or mandatory. For example, financial, data protection, safety, or industry regulators may require proposed changes to comply with legal or professional standards. Partners may collaborate with the organisation, but they do not normally enforce rules. Managers control internal resources and operations, but they are not the external rule-enforcing stakeholder category. Owners have financial or strategic interest in the organisation, but they do not normally monitor regulatory compliance unless they also hold a governance role. Since the question asks who monitors whether proposed changes fall within enforced rules, the correct stakeholder category is Regulators.