Part of Aloe which is medicinally important is

The correct option is D Leaves
Aloe vera is an evergreen perennial plant belonging to the family Asphodelaceae. It originates from Arabian Peninsula but grown wildly in tropical climates around the world. It is widely cultivated for agricultural and medicinal purposes. The leaves of Aloe are fleshy which are used for medicinal purposes in the treatment of skin.

So, the correct answer is 'Leaves'.