Final answer:
An insured who can return to work but is unable to perform all previous duties and suffers a loss of income might be eligible for Residual disability benefits.
Step-by-step explanation:
The correct definition that would cover an insured's permanent partial disability, when a person has returned to work but cannot perform all of his previous duties, is B. Residual disability. Residual disability benefits are paid to an insured who is not totally disabled but is unable to perform some of his or her duties due to an injury or illness, resulting in a decrease in income. Options A, C, and D do not accurately describe this situation; Presumptive disability usually refers to conditions that are almost always considered to be completely disabling by default, Total disability indicates that the person is unable to engage in any occupation for which they are reasonably suited, and Short-term disability typically covers temporary disabilities.