Answer:
d. A physical change occurred in which the iron remained iron, but lost one of its physical properties.
Explanation:
Iron is magnetic because domains can be arranged in single direction in presence of external magnetic field. It can be de-magnetized by heating, hammering and other methods.
When a iron is dropped in the lap, the domains get randomly aligned and it loses its magnetism. Magnetism is a physical property. There is no change in the chemical property.