(a) In the case of a child entitled to dependency and indemnity compensation who has attained the age of eighteen and who, while under such age, became permanently incapable of self-support, the dependency and indemnity compensation paid monthly to such child shall be increased by $286.

(b) If dependency and indemnity compensation is payable monthly to a person as a surviving spouse and there is a child (of such person’s deceased spouse) who has attained the age of eighteen and who, while under such age, became permanently incapable of self-support, dependency and indemnity compensation shall be paid monthly to each such child, concurrently with the payment of dependency and indemnity compensation to the surviving spouse, in the amount of $488.

(c) If dependency and indemnity compensation is payable monthly to a person as a surviving spouse and there is a child (of such person’s deceased spouse), who has attained the age of eighteen and who, while under the age of twenty-three, is pursuing a course of instruction at an educational institution approved under section 104 of this title, dependency and indemnity compensation shall be paid monthly to each such child, concurrently with the payment of dependency and indemnity compensation to the surviving spouse, in the amount of $243.