What kind of rider may be added to an individual disability income insurance policy to...

Detailed Answer in Step-by-Step Solution:

A cost of living (COLA) rider (B) adjusts disability income benefits to account for inflation, maintaining purchasing power.

Inflation guard (A) is more common in property insurance. Price escalation (C) and wage protection (D) are not standard disability riders.

The Virginia study guide describes the COLA rider as an optional feature in disability income policies, increasing benefits based on inflation indices like the CPI. Reference: Virginia Life, Annuities, and Health Insurance study guide, section on "Disability Insurance Riders."