Look at the graph below. A graph is shown with Absolute magnitude shown on y axis and Surface temperature in degree Celsius shown on x axis. The Dwarf stars are shown along a slanting line from coordinates 30,000 and minus 3 to 10,000 and minus 4. The Main Sequence stars are shown along a slanting line from coordinates 20,000 and minus 2 to 2,000 and minus 6. The giants are shown along a line parallel to the x axis from coordinates 5,000 and 2 to 2,000 and 3. The supergiants are shown along a line parallel to the x axis from coordinates 7,500 and 4 to 2,500 and 4. Point A has coordinates 20,000 and minus 4. Point B has coordinates 2,500 and minus 4. Point C has coordinates 5,000 and 2. Point D has coordinates 7,000 and 4. Which statement is true about Star A? (5 points)
a It is red in color.
b It is yellow in color.
c It is four times brighter than the sun.
d It is four times dimmer than the sun.