What endorsement adds coverage for employee use of automobiles during business use of rented autos?

The endorsement that adds coverage for employee use of automobiles during business use of rented autos is indeed the hired and nonowned auto liability. This coverage is specifically designed to protect businesses when employees use rented or non-owned vehicles for work-related purposes.

When employees utilize vehicles that are not owned by the business, such as rental cars or their personal vehicles for business duties, they still need liability protection in case of an accident. The hired and nonowned auto liability endorsement covers the business for liabilities arising from such uses, ensuring that employees have appropriate coverage while conducting business.

In contrast, the other options address different types of auto coverage. A personal auto liability policy is tailored for personal use of vehicles and does not extend to business activities involving rented autos. A commercial auto policy focuses on vehicles owned by the business and does not inherently cover non-owned or rented vehicles unless specific endorsements are added. The motor vehicle endorsement refers to a different type of adjustment and typically does not specifically address employee usage of rental cars in a business context. Hence, hired and nonowned auto liability is specifically suited for the scenario presented in the question.