15. The following income shall be chargeable to income-tax under the head “Salaries”—
(a) any salary due from an employer or a former employer to an assessee in the previous year, whether paid or not;
(b) any salary paid or allowed to him in the previous year by or on behalf of an employer or a former employer though not due or before it became due to him;
(c) any arrears of salary paid or allowed to him in the previous year by or on behalf of an employer or a former employer, if not charged to income-tax for any earlier previous year.
Explanation 1.—For the removal of doubts, it is hereby declared that where any salary paid in advance is included in the total income of any person for any previous year it shall not be included again in the total income of the person when the salary becomes due.
Explanation 2.—Any salary, bonus, commission or remuneration, by whatever name called, due to, or received by, a partner of a firm from the firm shall not be regarded as “salary” for the purposes of this section.