Which type of herpes simplex virus is primarily associated with cold sores?

The correct choice is HSV-1, which is primarily associated with cold sores. HSV-1, or herpes simplex virus type 1, is often responsible for oral herpes, characterized by lesions on or around the lips, commonly known as cold sores. This virus is highly contagious and is typically transmitted through close personal contact, such as kissing or sharing utensils.

While HSV-2, which is usually associated with genital herpes, can also cause oral infections, it is predominantly linked to sores in the genital area. Other viruses mentioned in the question, such as VZV (varicella-zoster virus), which causes chickenpox and shingles, and CMV (cytomegalovirus), which is related to a different range of conditions and is often asymptomatic, are not connected to cold sores. Thus, HSV-1 is recognized as the main cause of these common oral lesions.