The correct answer is A. Pyrex glass.
Pyrex glass is a type of glass that is made from borosilicate, which is a type of glass that is resistant to thermal shock. This makes it ideal for use in sun glasses, as it can withstand the sudden changes in temperature that can occur when you go from indoors to outdoors.
Flint glass is a type of glass that is made from lead oxide. It is a very hard glass that is often used in decorative items. However, it is not as resistant to thermal shock as Pyrex glass, so it is not a good choice for sun glasses.
Crooks glass is a type of glass that is made from lead oxide and barium oxide. It is a very heavy glass that is often used in laboratory equipment. It is not as resistant to thermal shock as Pyrex glass, so it is not a good choice for sun glasses.
Crystal glass is a type of glass that is made from lead oxide and potassium oxide. It is a very clear glass that is often used in decorative items. However, it is not as resistant to thermal shock as Pyrex glass, so it is not a good choice for sun glasses.