Which of the following is true regarding “drop-down” coverage that pays claims for which the underlying commercial liability policies do not provide coverage, regardless of aggregate limits?

I. It is provided by commercial excess liability insurance.
II. It is provided by commercial umbrella insurance.
III. It is typically subject to a self-insured retention.

(A) I only.
(B) II only.
(C) I and III only.
(D) II and III only.
(E) I, II, and III.