Final answer:
When in a Guaranteed Issue Window, all Medigap plans are guaranteed issue for a client.
Step-by-step explanation:
When in a Guaranteed Issue Window, all Medigap plans are guaranteed issue for a client. This means that a client can enroll in any Medigap plan of their choice without being denied or charged more due to pre-existing health conditions. Therefore, the correct answer to the question is D) All of the above.