If the President of India exercises his power as provided under Article 356 of the Constitution in respect of a particular State, then

The correct answer is B. Under Article 356(1)(b), once the President issues a Proclamation of State Emergency, the powers of the State Legislature can be exercised by or under the authority of Parliament. Parliament, not the President, makes the State laws, and the State Assembly is kept in suspended animation rather than removed.

• A is wrong: The Assembly is not automatically dissolved. The Proclamation must be approved by both Houses of Parliament within two months (Art. 356(3)). Dissolution happens only if Parliament separately approves it, and the Assembly can be dissolved only after such approval.
• C is wrong: Article 19 is suspended only during an external emergency under Article 352, and only through Article 358. Article 356 does not suspend Article 19. Article 359 deals with suspending enforcement of Part III rights during a national emergency.
• D is wrong: The President does not legislate directly for the State. Under Article 357, laws are made by Parliament, or by the President or others only under authority delegated by Parliament.

The core concept is the failure of constitutional machinery in a State. This links to Mains GS-II on Centre-State relations, the Sarkaria and Punchhi Commission recommendations, and the S.R. Bommai judgment (1994), which limited the misuse of Article 356.

Trap: Aspirants mix Article 356 with Articles 352, 358 and 359, and assume the President legislates personally during President's Rule.