What category do express, implied, bi-lateral, and unilateral fall under?

The terms express, implied, bi-lateral, and unilateral all fall under the category of contracts. An express contract is one in which the terms are explicitly stated, either orally or in writing. An implied contract, on the other hand, is formed through the actions or conduct of the parties involved, indicating their agreement even if it is not formally articulated.

A bilateral contract involves two parties where each side promises to perform an obligation, while a unilateral contract involves one party making a promise in exchange for performing a specific act by the other party. Understanding these classifications is crucial for anyone involved in real estate transactions, as they dictate the legal relationships and obligations between parties involved in leasing or renting properties. This distinction helps in navigating legal agreements effectively.

Other options like options, cancellation provisions, and surrenders of lease are unrelated classifications that do not encompass all four types of contracts mentioned. Each of those would pertain to specific terms and conditions in leasing scenarios but does not cover the comprehensive scope of contracts as the correct answer does.