A 25-year-old man persistently believes he has cancer despite repeated normal medical evaluations. He has no significant physical symptoms, but keeps demanding checkups. Most likely diagnosis is:

Correct option is B

Illness anxiety disorder (previously hypochondriasis) = preoccupation with having a serious disease despite absent/minimal symptoms and repeated reassurance.
Explanation of options: (a) ✘ Somatic symptom disorder = multiple physical complaints without findings. (b) ✔ Correct; illness anxiety = health worry without real symptoms. (c) ✘ Conversion = neurological deficits without organic cause. (d) ✘ Dissociative amnesia = loss of memory after trauma, not health worry.