The term "municipal relations" in the context of Centre-State relations in India is generally associated with the planning process. This term reflects how the central government interfaces with and exerts control over the state-level planning processes.

Option 1 discusses legislative control, where the central government may influence the state`s legislative efforts. However, this notion likely doesn`t reflect the term as it exists in municipal relations.

Option 2, which is about financial control, doesn`t represent municipal relations either. While the Centre does have influence over state finances through central grants and taxes, this isn`t specific to the concept of municipal relations.

Option 3 concerns administrative control, which isn`t the correct context. While the Centre does wield some authority over state administration, principally during Emergencies and through All India Services, this doesn`t constitute municipal relations.

Option 4, which is the correct answer, talks about the central government`s control in the planning process. The term "municipal relations" is specific to this area as it refers to the central government’s role in urban planning and managing municipal corporations.