Liability limits include "defense ____________" in addition to the policy's limits.

The correct answer is "cost," as the term "defense costs" refers to the expenses incurred by an insurer to defend the policyholder in a lawsuit, which is included within the liability limits of an auto insurance policy. This means that the defense costs are not additional to the policy limits; rather, they are considered part of the overall liabilities covered by the policy.

In a personal auto policy, when liability coverage is invoked due to an accident or legal claim, the insurer is responsible for both any damages awarded and the costs needed to defend the policyholder. This means that they may include costs related to attorney fees, court costs, and other related expenses. Recognizing this and understanding how these costs fit within the overall liability limits is essential for both insurance professionals and policyholders.

The other terms—charges, expenses, and fees—while they may seem similar, do not precisely match the standard terminology used in insurance policies regarding the inclusion of legal defense costs within liability coverage. Using "cost" captures the essence of what insurers cover in this context, making it the most accurate choice.