• Antiferromagnetism is the case where the magnetic moment of the atoms or molecules occur in accordance with spins of their electrons (usually in low temperatures) align themselves with a regular pattern with the neighbouring spins oriented in opposite directions cancelling each other’s magnetic moments which is option (iv) .

• Options (i) and

(ii) are simply the case for ferromagnetism when the substance is placed in a magnetic field the domains (substance particles grouped in different regions) orient themselves in the direction of the magnetic field which results in strong magnetism.

• Option (iii) is clearly the case of ferrimagnetism where the domains (tiny magnets) are aligned in parallel and anti-parallel orientation in unequal numbers which result in very weak magnetism.