What document must be provided to the customer when making a vehicle purchase at the dealership?

Answer: A — Warranty agreement

It is important for a customer to receive a copy of the warranty agreement when purchasing a vehicle at the dealership because it outlines the terms of the warranty and what is covered under it. This document also serves as proof of warranty in case any issues arise with the vehicle. While a notice of the "cooling off" period may also be provided to the customer, this only applies in select situations where the customer may have a right to return the vehicle within a certain timeframe. An insurance policy and employee handbook are not necessary documents for a vehicle purchase and would not be relevant to the customer in this scenario.