A 10 days female presents with a large patch of blue-gray pigmentation with irregular shape, unclear edges and normal skin texture involving buttocks and lower back. She is otherwise healthy and has no dysmorphic features. Which is the most probable diagnosis?

Congenital dermal melanocytosis (Mongolian spot) Congenital blue-grey macule found over the sacral skin area. Pigmentation initially deepens and then regresses completely by age 7 years Blue Nevi Benign skin lesion that is four times more common in children, typically affecting the extremities and face. Small, slightly elevated, and blue-black lesions. However, blue-black papules and nodules that are new or growing must be evaluated to rule out nodular melanoma Infantile hemangioma Strawberry, capillary, or cavernous hemangioma Benign endothelial proliferation that represents the most common tumor in infancy. Most commonly on head and neck areas. Superficial ones presents as bright red-colored plaque. Deep ones presents as a soft dermal or sub cutaneous nodule with a bluish-purple color. More than 90% of untreated hemangiomas involute, that is, attain maximal regression by 9 years of age. Up to 30% of hemangiomas leave postinvolution changes including hypopigmentation, scarring, telangiectasia, and fibrofatty tissue.