The Umbra of a Sunspot Is About 1500 K Cooler

Multiple Choice

The umbra of a sunspot is about 1500 K cooler than the surrounding solar photosphere. How does the light from the umbra compare with the light from the rest of the photosphere?

A) The umbra and the surrounding photosphere both emit light of the same color and the same intensity (per square meter) because they are both in the photosphere.
B) The light from the umbra is bluer.
C) The light from both the umbra and the surrounding photosphere are the same color, but the umbra emits less light per square meter.
D) The light from the umbra is redder.