The correct answer is option 'D' which states that a change in which the original substance can be obtained back by change of conditions is both a reversible change and a physical change.

Reversible Change:
A reversible change is a change that can be undone or reversed by simply changing the conditions or factors that caused it. In other words, the original substance can be obtained back by altering the conditions of the change. Reversible changes are typically physical changes that involve a change in the state or form of a substance.

Physical Change:
A physical change is a change in which the substance undergoes a change in its physical properties without forming any new substances. Physical changes do not produce new substances, and the original substance can usually be recovered. Examples of physical changes include changes in state (e.g., melting, freezing, boiling), changes in shape or size, and changes in appearance.

Explanation:
When a change is both reversible and a physical change, it means that the original substance can be recovered by simply changing the conditions or factors that caused the change. This implies that no new substances are formed during the process, and the change only affects the physical properties of the substance.

For example, consider the melting of ice. When heat is applied to ice, it melts and changes state from a solid to a liquid. However, if the temperature is lowered again, the liquid water will freeze and change back to ice. In this case, the change is reversible because the original substance (ice) can be obtained back by changing the temperature conditions. It is also a physical change because no new substances are formed during the process.

Similarly, other physical changes such as dissolving of a solute in a solvent, evaporation of a liquid, condensation of a gas, etc., can also be reversed by changing the conditions. These changes involve a change in physical properties but do not result in the formation of new substances.

In summary, a change in which the original substance can be obtained back by changing the conditions is both a reversible change and a physical change. These changes only affect the physical properties of the substance and do not involve the formation of new substances.

D is the correct answer