When a health insurer requires a covered individual to undergo a physical examination, who pays...

Detailed Answer in Step-by-Step Solution:

If a health insurer requires a physical exam (e.g., for underwriting or claims), the insurer pays the cost (D), as it’s their condition for coverage or payment.

The premium payor (A), insured (B), or patient (C) aren’t responsible for insurer-mandated exams.

The Virginia study guide specifies that insurer-required exams, such as for contesting claims, are at the insurer’s expense, per the physical examination provision. Reference: Virginia Life, Annuities, and Health Insurance study guide, section on "Health Insurance Policy Provisions."