The correct answer is option 2: Stratosphere. Ozone is an important component of the Earth`s atmosphere and is found in different layers. The majority of the ozone is concentrated in the stratosphere, which is the second layer of the atmosphere located above the troposphere. The stratosphere starts approximately 10 kilometers above the Earth`s surface and extends up to about 50 kilometers. The ozone layer in the stratosphere plays a critical role in protecting life on Earth by absorbing harmful ultraviolet (UV) radiation from the Sun. This absorption prevents much of the UV radiation from reaching the Earth`s surface, where it can cause damage to living organisms and the environment. Therefore, the stratosphere is where most of the ozone in the Earth`s atmosphere is found.