Final answer:
To relieve abdominal pain, elevating the head slightly with a pillow and placing a support under the knees can be helpful.
Step-by-step explanation:
With a patient suffering abdominal pain, it is frequently helpful to elevate the head slightly with a pillow (option 1) and place a support under the knees (option 3). These positions can help relieve discomfort and promote relaxation for the patient. Performing the examination in the Trendelenburg position (option 2), where the head is lower than the feet, may not be necessary or helpful in this case. Therefore, the correct answer is Option D. 1 and 3 only.