What is the role of the European Commission in the EU?

The European Commission serves as the executive arm of the European Union and is primarily responsible for proposing legislation, implementing decisions, and managing the day-to-day operations of the EU. This includes ensuring that EU law is applied and implemented effectively across all member states, thus playing a crucial role in fulfilling the EU's goals.

The Commission acts as a guardian of the treaties, making sure that EU legislation is adhered to, which encompasses a wide variety of areas, including internal markets, competition policy, and data protection. It also represents the EU internationally, negotiating on behalf of the EU with other countries and international organizations.

In contrast, while the other choices represent functions that may be part of the broader context of EU governance (such as the European Parliament's legislative role, or monitoring compliance and conducting audits, which may involve other EU bodies), they do not accurately capture the primary function of the European Commission. Thus, the primary role of the Commission is aptly reflected in the correct answer regarding its responsibilities in implementing decisions and policies within the EU framework.