What is the most common malignant skin cancer?

A. Basal cell carcinoma is the most common malignant skin cancer, especially in fair-skinned individuals with frequent sun exposure. It grows slowly and rarely metastasizes. B. Melanoma is less common but more aggressive and more likely to metastasize, making it the most dangerous type, but not the most common. C. Squamous cell carcinoma is the second most common form of skin cancer, but less common than basal cell carcinoma. D. Actinic keratosis is a precancerous lesion, not a malignant cancer, although it can develop into squamous cell carcinoma if untreated.