The correct answer is (d) All of these.
Under Section 21 of the Hindu Adoption and Maintenance Act 1956, a Hindu is bound to maintain his or her father, mother, and widow, so long as they do not remarry. The word “dependent” is defined as a person who is unable to maintain himself or herself by reason of age, illness, or infirmity.
Option (a) is incorrect because it only mentions the father. The Act also includes the mother and widow.
Option (b) is incorrect because it only mentions the mother. The Act also includes the father and widow.
Option (c) is incorrect because it only mentions the widow. The Act also includes the father and mother.