According to the Theoretical Model of the Sun Shown Graphically

According to the theoretical model of the Sun shown graphically in Figure 11-23 in the text, where is the vast majority of solar energy generated?

A) within 0.60, or 60%, of a solar radius of the Sun's center
B) throughout the whole Sun
C) within 0.25, or 25%, of a solar radius of the Sun's center
D) within 0.8, or 80%, of a solar radius of the Sun's center