Final answer:
The patient understands the teaching when they state using their hands instead of a washcloth to clean the radiation area after radiation therapy.
Step-by-step explanation:
To determine if the patient understands the teaching, we need to look for statements that demonstrate knowledge about the precautions and aftercare involved in radiation therapy for esophageal cancer. Option A is incorrect because washing off the ink markings is not recommended as it helps with accurate targeting. Option B is correct because using hands instead of a washcloth reduces the risk of skin irritation. Option C is incorrect because being out in the sun after radiation treatments can increase the risk of skin damage. Option D is incorrect because using a heating pad on the neck can worsen side effects during radiation therapy.
Therefore, the correct statement indicating understanding of the teaching is B. The patient acknowledges using hands rather than a washcloth to clean the radiation area.