The correct answer is B — limits of insurance are used up. Under Businessowners liability coverage, the insurer generally has both a duty to indemnify the insured for covered damages and a duty to defend qualifying suits. However, the defense obligation does not continue indefinitely after the applicable liability limit has been exhausted in the manner prescribed by the policy.

Standard BOP analysis provides that the insurer's duty to defend ends when the applicable limit of insurance has been used up through payment of judgments or settlements. Simply deciding that the insured has made too many claims does not terminate the defense obligation.

That qualification matters. The insurer ordinarily cannot simply tender the limit without satisfying the policy wording and abandon an otherwise ongoing defense. Exhaustion must occur according to the contract.

Failure to pay taxes, option A, has no connection to the insurer's contractual defense duty. Premium nonpayment, option C, can eventually result in lawful cancellation or termination of coverage, but it does not describe the specific liability-form provision asked by this question. Option D has no contractual basis.

The Series 17-70 BOP section tests Business Liability, defense obligations, limits of insurance, exclusions, who is an insured, and liability conditions.

Therefore, B is correct.