(a) "Widow". Only the widow, who has not remarried, of a deceased member or deceased retired member of the uniformed force of a police or fire department;
(b) "Dependent children". Only children under the age of eighteen of a deceased member or deceased retired member of the uniformed force of a police or fire department;
(c) "Dependent parents". Only a father or mother, or both collectively if both are living, of the deceased member or deceased retired member of the uniformed force of a police or fire department, where neither dependent widow nor dependent children under age eighteen survive such member or retired member.