Read the following excerpt from a US court opinion:
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of the contents of its own policy ... In addition, notice of facts which would cause a reasonable person to inquire further im poses a duty of investigation upon the insurer, and failure to investigate constitutes a waiver of all powers or privileges which a reasonable search would have uncovered. Steptore, 643 So.2d at 1216. If a policy requires an insurer to defend a claim, then the insurer must do so, even if it ultimately may not be liable under the policy. Peavey Company v. M/V ANPA, 971 F.2d 1168, 1175 (5th Cir.1992). An insurer can supply its insured with a defense and simultaneously contest its obligation to provide coverage by reserving its right to refuse coverage in a timely manner. Id. An insurer that tardily reserves its rights waives defenses to coverage. Id. at 1175-76 . a. The Johnson Lawsuit It is undisputed that
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What is the most suitable continuation to the opinion? Your options are:
A. holding that insurer who after being told of occurrence contacted insureds attorney for information should have issued reservation of rights letter within a reasonable time after  it was informed of the occurrence
B. holding that the insurer was estopped from asserting coverage defenses when it waited to file a declaratory action until 10 months after it had notice of the claim and several months after it had notice of a potential settlement of the underlying litigation
C. holding that insurer that waited five months after being informed of occurrence and two months after being informed of suit against insured to deliver reservation of rights letter waived its noncoverage defense
D. holding that an insured waited unreasonably long in first notifying an insurer of a lawsuit five months after its filing
E. holding despite a reservation of rights that when the insurer provides a defense to its insured the insured has no right to interfere with the insurers control of the defense and a stipulated judgment between the insured and the injured claimant without the consent of the insurer is ineffective to impose liability upon the insurer
Reply with [A, B, C, D, E] only.