Which of the following could replace 'variant' as used in the passage?

Directions: Read the following passage carefully and select the most suitable option according to the corresponding number in the passage.

What are Pimples?
Acne known as Pimples is a common disorder developed in teenagers and at times in young adults due to the inflammation of skin, as superficial skin eruption caused by the blockage of skin pores.

W hen dealing with the phenomenon of pimples it is usually youth pimples that come to mind. Youth pimples stand out from pimples in grown ups in that the latter variant is more likely to be accompanied by oily skin. Adults are considered to respond better to treatment with antibiotics than youths. The emergence of acne has its origin in the production of tallow in the skin on one hand, and in the fact that openings of the surface of the skin of sebaceous glands is stopped up, usually by horn cells (skin cells).