Select the option that can be used as a one-word substitute for the given group of words.
"A deal of agreement done in a company or firm."

Let's evaluate the definitions of the options:
* Contract: A written or spoken agreement, especially one concerning employment, sales, or a tenancy, that is intended to be enforceable by law.
* Conformity: Compliance with standards, rules, or laws.
* Acceptance: The action of consenting to receive or undertake something offered.
* Concurrence: The fact of two or more events or circumstances happening or existing at the same time; agreement.

Thus, "Contract" is the most appropriate one-word substitute.