Which element has the chemical symbol 'O'?

The element with the chemical symbol 'O' is oxygen. Oxygen is a vital element in the periodic table, known for its role in supporting life through respiration in living organisms and its presence in various chemical compounds, such as water (H2O) and carbon dioxide (CO2). It is a nonmetal and is essential for combustion, as it acts as an oxidizer.

Osmium, while a real element, has the chemical symbol 'Os', which distinguishes it from oxygen. Gold is represented by the symbol 'Au', derived from its Latin name 'Aurum', and is well-known for its properties as a precious metal. Oganesson, a recently discovered element, has the symbol 'Og' and is a synthetic element that is not found in nature. Thus, oxygen is the only choice among the options provided that correctly corresponds to the symbol 'O'.