Insurance under a group life insurance policy may be extended to cover:
(1) the spouse of each individual eligible to be insured under the policy;
(2) a natural or adopted child of each individual eligible to be insured under the policy if the child is:
(A) younger than 25 years of age or an older age stated in the policy; or
(B) physically or mentally disabled and under the parents' supervision; or
(3) a natural or adopted grandchild of each individual eligible to be insured under the policy if the child is younger than 25 years of age or an older age stated in the policy.