A 20-year-old woman repeatedly visits clinics with complaints of headache, chest pain, and fatigue. All investigations are normal. She insists on repeated check-ups despite reassurance. Most likely diagnosis is:

Correct option is C

Illness anxiety disorder (hypochondriasis) = preoccupation with having a serious disease despite absent or minimal symptoms, leading to repeated medical visits.
Explanation of options: (a) ✘ Dissociative = memory loss, trance states, not repeated health worry. (b) ✘ Somatization = multiple physical complaints with no cause, but actual symptoms dominate, unlike here. (c) ✔ Correct; here, anxiety about illness without real symptoms = illness anxiety disorder. (d) ✘ Conversion = neurological deficits (paralysis, blindness), not persistent health worries.