$47.$ Irth Movers Excavation hires a subcontractor, Ellison Excavation, to help them complete a backlog of work. Ellison's CGL policy includes a standard blanket additional insured endorsement. Which of the following will trigger automatic additional insured status for Irth Movers under Ellison's CGL policy?

$($Search Chapter $10)$

a$.$ Ellison is required by contract to add Irth Movers as an additional insured.

b$.$ Ellison is required by contract to defend and indemnify Irth Movers.

c$.$ Ellison's operations for Irth Movers have commenced.

d$.$ Irth Movers agrees to pay Ellison for work performed.