$18.$ Kleinman Contracting has a number of construction projects underway, including a school, a restaurant, and an auto repair shop. Each project is separately insured. To avoid double coverage on workplaces that are insured separately or self$-$insured, what endorsement should Kleinman Contracting attach to its workers compensation policy?

$($Search Chapter $2)$

a$.$ the workplaces$-$other insurance endorsement

b$.$ the designated workplaces exclusion endorsement

c$.$ the specified workplaces exclusion endorsement

d$.$ the separate insurance endorsement