Which of the following is NOT a tenant obligation according to the Landlord-Tenant Act?

The correct answer is rooted in the specific obligations outlined in the Washington Landlord-Tenant Act. A tenant's responsibilities primarily focus on maintaining the rental property in a clean and sanitary condition, properly disposing of garbage, and returning the property in good condition at the end of the lease, accounting for normal wear and tear.

While tenants are expected to maintain the property, the obligation to keep the premises "up to code" typically falls more on the landlord's responsibilities. Landlords are in charge of ensuring that the property meets all building and safety codes, making this not a direct tenant obligation. The expectations around cleanliness and sanitation, including garbage disposal, are clearly defined as tenant obligations since they pertain to the daily use and maintenance of the unit.

Thus, the first option does not align with the typical requirements imposed on tenants and is why it is identified as NOT a tenant obligation under the Act.