Step 1: Understanding McCabe $\Delta$L Law.
The McCabe $\Delta$L law primarily applies to crystal growth and describes how the growth rate is influenced by the degree of supersaturation. Supersaturation is a key factor in the formation of crystals, and the growth rate is linear with respect to the degree of supersaturation in most cases. This law is not related to the molar heat of vaporization or crystal size.
Step 2: Conclusion.
The correct answer is (2), as McCabe $\Delta$L law states that the linear crystal growth rate depends on the degree of supersaturation.