Question

Which of the following materials cannot be used to make a lens?

Answer 1

Correct option is D. Clay
We know that water and glass are transparent material. Therefore, they can be used to form the lens.

There is some plastic that is transparent so the plastic can be used to make a lens but the clay is a $$opaque$$ material so the light can't transmit through it so $$clay$$ can't be used for making the lens.