Tenant is a dentist and rents office space from Landlord. During year 3 of his 10-year lease, Tenant decided to make some improvements to the space he was renting. Tenant asked Landlord for permission, and Landlord freely gave it without any conditions. Later, after Tenant began to make the improvements, Landlord changed her mind and revoked permission. The improvements cost Tenant $5,000 but are uncompleted and have no value. What is Tenant's best theory of recovery against Landlord?

		Promissory estoppel.
		Quasi contract.
		Breach of contract.
		False pretenses.
		I do not know