The correct answer is (c). A constitutional amendment bill can be introduced in any of the two Houses of Parliament, i.e., the Lok Sabha or the Rajya Sabha. After it is passed by both Houses, it is sent to the President for his/her assent. If the President gives his/her assent, the amendment becomes a part of the Constitution.
Option (a) is incorrect because a constitutional amendment bill can be introduced in either House of Parliament. Option (b) is incorrect because a constitutional amendment bill does not have to be introduced first in the Rajya Sabha. Option (d) is incorrect because a constitutional amendment bill does not have to be approved by the President before it is introduced in Parliament.