Oxidation is a process which involves:(a) Addition of oxygen(b) Removal of hydrogen(c) Loss of electrons(d) All of the above.

The correct answer is (d) All of the above.

Oxidation is a chemical process that involves various phenomena, including the addition of oxygen, removal of hydrogen, and loss of electrons. Let's break down each of these aspects:

(a) Addition of oxygen: In many cases, oxidation occurs when a substance combines with oxygen. This can be seen in reactions like combustion, where a fuel reacts with oxygen to produce heat and light. For example, the oxidation of iron results in the formation of iron oxide (rust) when iron reacts with oxygen in the presence of moisture.

(b) Removal of hydrogen: Oxidation can also involve the removal of hydrogen from a substance. This is often observed in reactions where hydrogen is displaced by another element or compound. For instance, when hydrogen gas reacts with chlorine gas, hydrogen chloride is formed, and the hydrogen is oxidized as it loses an electron.

(c) Loss of electrons: Oxidation involves the loss of electrons from a species. Electrons carry negative charge, and when an atom or ion loses electrons during a chemical reaction, it is said to be oxidized. This loss of electrons leads to an increase in the oxidation state or oxidation number of the atom or ion. For example, when magnesium reacts with oxygen to form magnesium oxide, magnesium loses two electrons and is oxidized from its elemental state (Mg^0) to an ion with a +2 oxidation state (Mg^2+).

Therefore, oxidation encompasses the addition of oxygen, removal of hydrogen, and loss of electrons, making option (d) "All of the above" the correct choice.