Is anesthesia required for dilation and curettage?

Depends why. Often a d & c may be done under sedation with Propofol and other meds such as versed or fentanyl. The gyn doctor may use local anesthesia around the cervix. If it's an emergency situation where the patient doesn't have an empty stomach, if the patient is extremely obese, or if there is heavy bleeding, general anesthesia may be safest. The ob/gyn and anes doctors will decide the best plan.
Many. D+c can be done with a variety of techniques. Can be mac/sedation helped with pudendal block, general, spinal. Depends on your health and aspiration risk, what you prefer, and anesthesiologist comfort level. You can discuss with your anesthesia provider your preferences.
Usually general. In my hospital this is usually done under a light general anesthetic.
Many. D+c can be done with a variety of techniques. Can be mac/sedation helped with pudendal block, general, spinal. Depends on your health and aspiration risk, what you prefer, and anesthesiologist comfort level. You can discuss with your anesthesia provider your preferences.