Final answer:
The visible surface of the Sun called the photosphere has a temperature just under 6000 K, making option 1) Photosphere the correct answer.
Step-by-step explanation:
The visible surface of the Sun, where the temperature averages just under 6000 K, is called the photosphere. This makes the correct answer to the student's question 1) Photosphere. The photosphere has a temperature that ranges from 4500 K to about 6800 K, with a typical value of around 5800 K. Sunspots, which are cooler regions on the photosphere, appear darker and have temperatures of about 3800 K. Beyond the photosphere lies the chromosphere and the corona, the latter being the outermost part of the Sun's atmosphere with temperatures reaching a few million K.