Final answer:
The correct answer is that both Assertion and Reason are correct but Reason is not the correct explanation for Assertion. Optical density and mass density are distinct properties; while not directly related, certain materials may exhibit parallels due to their atomic arrangement. Therefore, the correct option is B.
Step-by-step explanation:
The Assertion states that if the optical density of a substance is more than that of water then the mass density of a substance can be less than water. The Reason claims that optical density and mass density are not related. In this context, the correct answer is:
B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
While it is true that a substance can have a higher optical density and still have a lower mass density than water (for example, aerogels can have very low mass densities but can exhibit high optical densities due to their structure), the implication that these two types of density are unrelated is incorrect. Optical density is a measure of how a substance bends light (refractive index), and mass density refers to the mass per unit volume of a material. They are different properties and one does not directly predict the other; however, in some cases, materials with higher optical densities can also have higher mass densities due to the arrangement of the atoms within the material. This, however, is not a strict rule, and there is no direct relationship that allows us to universally predict mass density from optical density, or vice versa.