Article 102(1)(a) is the office-of-profit disqualification — option 4.

The scheme of Article 102. It lists the grounds on which a person is disqualified from being chosen as, or from being, a member of either House of Parliament :

Why the rule exists. It rests on the separation of powers. A legislator’s duty is to hold the executive to account, and that duty is compromised if the same person draws a salary or benefit from the executive’s gift. The framers took the principle from British practice, where it dates back to the Act of Settlement of 1701.

What counts as an office of profit. The Constitution does not define it. The courts have laid down tests — whether the government makes the appointment, whether it can remove the holder, whether it pays the remuneration, and whether the office carries functions of a governmental character. What matters is that the office is capable of yielding profit, not that the holder actually took any pay.

The escape clause. The words “other than an office declared by Parliament by law not to disqualify” allow Parliament to exempt particular offices, which it has done through the Parliament (Prevention of Disqualification) Act, 1959. Article 191 makes identical provision for State Legislatures, and the question of disqualification is decided by the President or Governor on the opinion of the Election Commission, under Articles 103 and 192.

Hence, the answer is Article 102 (1) (a).