A. General liability insurance.
B. Surety bonds.
C. Business interruption insurance.
D. Commercial property coverage.

My answer would be C. Business Interruption Insurance.

Here is my reasoning:

If you are an agent selling a policy to your customer, the other 3 items are all coverages where claims would result in payments to other parties. A claim under business interruption coverage would trigger a payment to YOUR CUSTOMER for his loss of business income following a claim.