Which one of the following components is added to optical glass to cut off UV rays?

Cerium oxide (CeO2) is the chemical component added to optical glass to absorb and cut off ultraviolet (UV) radiation. This type of glass, famously known as Crookes glass, contains cerium and other rare earth elements that provide a high absorption capacity for UV rays while remaining transparent to the visible spectrum. This makes it ideal for high-quality sunglasses and protective eyewear. Other oxides listed serve different functions:

• Copper oxide is used to give glass a turquoise, green, or red tint.
• Manganese oxide is primarily used as a decolourizer to neutralize the green tint of iron impurities, or in higher concentrations to produce purple glass.
• Cobalt oxide is a powerful coloring agent used to produce deep blue glass.