(A)seborrheic keratosis: Seborrheic keratoses are common epidermal tumors consisting of a benign proliferation of immature keratinocytes
(B)sebaceous hyperplasia: Sebaceous hyperplasia is the term used for enlarged sebaceous glands seen on the forehead or cheeks of the middle-aged and elderly. Sebaceous hyperplasia appears as small yellow bumps up to 3 mm in diameter. Close inspection reveals a central hair follicle surrounded by yellowish lobules.
(C)nevus sebaceous: A nevus sebaceous is a rare type of birthmark that can be found on the face, neck, forehead, or scalp. While it can appear anywhere on the head, it most often occurs on the scalp. Though it's technically classified as a hair follicle tumor and is associated with other conditions, a nevus sebaceous is benign.