Answer:
Among the given choices, the coolest stars is O.C. White dwarf.
Step-by-step explanation:
White dwarfs are the remnants of stars that have exhausted their nuclear fuel and have collapsed to a very dense state. They are relatively cool compared to other types of stars, with surface temperatures typically ranging from about 4,000 to 12,000 degrees Celsius (7,232 to 21,632 degrees Fahrenheit). In contrast, red giants, blue giants, and yellow dwarfs are all hotter and more luminous at their surfaces than white dwarfs.