Final answer:
The most favorable definition of disability for Devin is the 'own occupation' definition because it allows him to receive benefits if he's unable to perform his current job, unlike the 'any occupation' definition which is less advantageous.
Step-by-step explanation:
The definition of disability in a group disability income insurance plan that would provide the most favorable protection for Devin is the “own occupation” definition of disability. This definition considers Devin to be disabled if he is unable to perform the duties of his own specific occupation, allowing him to receive benefits even if he could still work in a different capacity. By contrast, an “any occupation” definition would only consider him disabled if he is unable to perform the duties of any job suited to his education and experience, which is generally less advantageous for the insured.