Loss of part or function -

Ans. is 'a' i.e., Impairment o According to WHO definitions,Disease: Any abnormal condition of an individual that impairs functionImpairment: Any loss or abnormality of psychological, physiological or anatomical structure or functionDisability: (Because of impairment,) any restriction or inability to perform an activity in a range considered normal for a human beingHandicap: A disadvantage for a given individual, resulting from an impairmentv'disability, that limits/prevents fulfillment of a role considered normal (depending on age, sex, social, cultural factors) for that individual