What is an official written statement saying you don't have to do something?

The correct answer is a waiver. A waiver is an official written statement or document that allows an individual to be exempt from a specific obligation or requirement. It signifies that the person is relinquishing the right or duty to do something that might typically be expected of them. In legal and official contexts, waivers are often used to protect individuals or organizations from liabilities or obligations, hence their importance in various applications and agreements.

The other options represent different concepts. A permit typically refers to authorization granted to do something, such as a license or permission. An agreement is a mutual arrangement between parties but does not imply exemption from a requirement. A contract is a formal and legally enforceable agreement between parties but does not inherently imply that an obligation is being waived; rather, it usually stipulates obligations and responsibilities.