Final answer:
A Disability Income policy where the insurer can change the premium but must renew the policy until the policyholder turns 65 is known as Guaranteed renewable. It is different from non-cancelable, optionally renewable, and conditionally renewable policies.
Step-by-step explanation:
The type of renewability that best describes a Disability Income policy that covers an individual until the age of 65, where the insurer retains the right to change the premium rate, is Guaranteed renewable. This policy type means the insurer is obligated to renew the policy every year up to a certain age (such as 65) as long as the premiums are paid by the policyholder.
However, the insurer has the right to increase the premium for the entire class of similar policies, not just for an individual policyholder. A non-cancelable policy is where both the premium rate and the benefits cannot be changed by the insurer. An optionally renewable policy allows the insurer to decide whether to renew the policy at the end of each term. Lastly, a conditionally renewable policy imposes conditions under which the policy can be renewed, such as the insured's continuing employment.