In what form must the rent increase notice be given to the tenant?

The correct choice is written notice, as it is essential to have a formal and verifiable way of communicating changes regarding rent. A written notice serves as a clear record that can be referenced in the future, ensuring that both the landlord and tenant have a common understanding of the terms being modified. This form of communication helps protect the rights of both parties and provides a legal framework for addressing any disputes that may arise.

Verbal notices may lead to misunderstandings, as they lack documentation and are often difficult to enforce. Similarly, while email communication is commonly used, it may not fulfill legal requirements in every jurisdiction unless specified by law. Phone calls are also not suitable because they do not provide a physical record of the communication. Thus, providing notice in writing is the most reliable and legally recognized method for notifying tenants about rent increases.