Final answer:
Acne is caused by the infection and inflammation of sebaceous glands, which produce sebum. Excess sebum and bacterial growth are primary factors in the development of acne lesions. Thus, the option a is correct answer.
Step-by-step explanation:
Acne is a skin condition resulting from the infection of sebaceous glands. These glands produce an oily substance called sebum, which lubricates the skin and hair. When these glands become overactive, as often occurs during puberty due to hormonal changes, excess sebum can accumulate and block hair follicles, leading to the formation of acne. The blockage creates an environment where bacteria such as Propionibacterium and Staphylococcus can thrive, causing inflammation and the development of acne lesions.
To answer the question, acne is a disorder associated with a) sebaceous glands.