With reference to Article 31C of the Indian Constitution, consider the following statements:

I. Originally, Article 31C protected laws implementing Article 39(b) and 39(c).

II. The 42nd Amendment expanded Article 31C protection to all Directive Principles.

III. The Supreme Court struck down the 42nd Amendment expansion of Article 31C.

IV. Article 31C completely excludes judicial review.

Which of the statements given above are correct?