With reference to Article 31B and the Ninth Schedule, consider the following statements:

I. Laws placed in the Ninth Schedule are completely immune from judicial review.

II. Article 31B was inserted by the First Constitutional Amendment.

III. Laws inserted in the Ninth Schedule after 24 April 1973 are subject to Basic Structure review.

IV. Article 31B protects laws only from challenge under Article 14.

How many of the statements given above are correct?