Solid camphor is insoluble in water but is soluble in vegetable oil. The best explanation for this behavior is that camphor is $a\left(n\right)$ :

A crystalline material that is either colorless or white and has a strong mothball-like odor is known as CAMPHOR. water-density-like in terms of density produces combustible fumes at 150°F. utilized in the creation of flavorings, medications, and mothproofing’s.

Therefore, Solid camphor is insoluble in water but is soluble in vegetable oil. The best explanation for this behavior is that camphor is $a\left(n\right)$ molecular solid.

Hence, option C is correct.