阅读短文，选出填入空格最合适的一项： Under the new rules, …

阅读短文，选出填入空格最合适的一项：

Under the new rules, landlords will be ___ for keeping rental homes safe and in good repair. If a heater breaks down in winter, the landlord must fix it within forty-eight hours. Tenants who report problems cannot be asked to leave because they complained. Supporters say the rules will protect families who cannot afford to move. Some landlords, however, worry that their repair costs will rise.