Final answer:
Pain level is subjective data in patient information gathering as it relies on the patient's personal experience and cannot be objectively measured, unlike blood pressure, body temperature, and height.
Step-by-step explanation:
Among the options listed, d) Pain level is considered subjective data in information gathering from a patient. Unlike objective data such as blood pressure, body temperature, and height, which can be measured and confirmed independently of the patient's input, pain level is subjective because it is based on the patient's personal experience and cannot be directly measured by external means. A common method of quantifying pain is using the Wong-Baker Faces pain-rating scale, where patients rate their pain on a scale from 0 to 10. It is essential to recognize subjective data like pain level as they are key components in assessing a patient's condition and planning treatment despite their inherent variability.