Option 1: Both the statements are individually true and statement II is the correct explanation of statement I.

This option suggests that both statements are true and that statement II provides the correct explanation for statement I. However, statement I mentions that Crooke`s glass for spectacles contains rare earth metal oxides of praseodymium and neodymium, while statement II states that Crooke`s glass is characterized by its ability to absorb ultraviolet light and transmit visible light completely. There is no explanation provided in statement II about the inclusion of rare earth metal oxides of praseodymium and neodymium in Crooke`s glass. Therefore, option 1 is incorrect.

Option 2: Both the statements are individually true but statement II is not the correct explanation of statement I.

This option acknowledges that both statements are true. Statement I correctly states that Crooke`s glass for spectacles contains rare earth metal oxides of praseodymium and neodymium. However, statement II does not provide an accurate explanation of statement I. Instead, it talks about Crooke`s glass`s ability to absorb ultraviolet light and transmit visible light completely, without specifically mentioning the rare earth metal oxides. Therefore, option 2 is the correct answer.

Option 3: Statement I