Option 1: Sodium (Na) is a highly reactive metal and it reacts vigorously with both oxygen and water. When sodium comes into contact with oxygen, it forms sodium oxide. In the presence of water, sodium reacts to form sodium hydroxide and hydrogen gas. Therefore, sodium is not the correct answer.

Option 2: Copper (Cu) does not react with oxygen at room temperature, however, it does react slowly with oxygen at higher temperatures to form copper oxide. Copper also does not react with water or dilute acids. Therefore, copper is not the correct answer.

Option 3: Iron (Fe) reacts with oxygen in the presence of air to form iron oxide. It also reacts with dilute acids to produce hydrogen gas. Therefore, iron is not the correct answer.

Option 4: Gold (Au) is a noble metal, which means it is very unreactive. It does not react with oxygen, water, or most acids. Gold is known for its resistance to corrosion and it maintains its shiny appearance over time. Therefore, gold is the correct answer to the question.

In conclusion, the metal that does not react with oxygen, water, or acids is gold (Au).