The correct answer is 4. TENS is commonly used to alleviate pain and discomfort by interfering with pain signals sent to the brain, promoting the release of endorphins, and improving blood circulation. Although the spinal level varies, the overall consensus is that the electrodes are placed higher and on the back initially and then moved lower and to the anterior pubic region as labor progresses. It's important to note that TENS may not provide complete pain relief, especially during active labor when contractions can be intense. Some women find TENS to be a helpful addition to their pain management plan, while others may find it less effective.