The correct answer is option 2: 7.

In the human body, the cervical vertebrae are the seven vertebrae that make up the uppermost part of the spinal column, also known as the neck region. These vertebrae are numbered C1 to C7, with C standing for cervical. Each cervical vertebra is a small and delicate bone that has a unique structure, allowing for flexibility and movement of the neck. The cervical vertebrae are responsible for supporting the weight of the head, protecting the spinal cord, and facilitating the movements of the neck, including rotation, flexion, and extension. It is important to note that the number of cervical vertebrae in humans is consistent, and any deviation from this number would be considered abnormal.