The answer to your fine question is D.
As stars get older they get cooler and you know when you light a flame the part at the bottom is hotter so its also applies to stars, the star is very hot because it is newer and has more gas so it appears blue to us
I guess the "mekong" river.
~ Drought hazard is generally high for semiarid areas, such as Northeastern and Southern South America, Northern, Southwestern and Horn of Africa, Central Asia, Australia, West U.S. and the Iberian Peninsula; and low for tropical regions, such as the Amazon, Central Africa and Southern Asia