Which should be the first sentence after rearrangement?

Rearrange the following sentences which are jumbled, to form a meaningful paragraph and answer the questions that follow it.
A.      People with an illness anxiety disorder (IAD) experience persistent anxiety or fear of developing or having a serious medical illness that adversely affects their daily life.
B.      This fear persists despite normal physical examination and laboratory testing results.
C.      People suffering from IAD pay excessive attention to normal bodily sensations (such as functions of digestion or sweating) and misinterpret these sensations as indicators of severe disease.
D.      It is defined by excessive worry about having or developing a serious undiagnosed medical condition. E.       Illness anxiety disorder (previously called hypochondriasis, a term which has been revised in the DSM-5 due to its disparaging connotation) is a psychiatric disorder.