Which of the following would be considered an additional benefit in an auto insurance policy?

In the context of an auto insurance policy, additional benefits typically refer to enhancements or supplementary coverages beyond standard protections. Coverage for temporary loss of use due to theft falls into this category, as it addresses the inconvenience and potential financial impact of not having access to a vehicle when it's stolen. This benefit helps ensure that the insured can still get around while their primary vehicle is unavailable, thus providing valuable support during a stressful time.

The other options do not align with the concept of additional benefits. Payment of legal fees might be part of an existing coverage but isn't classified as an additional benefit. Increased premiums after accidents are a consequence of claims rather than a benefit, and the exclusion of aftermarket modifications serves as a limitation rather than an enhancement to coverage. Thus, focusing on the comprehensive support provided by temporary loss of use underscores why this choice is recognized as an additional benefit.