Answer:
The most appropriate answer would be A) Carbohydrates.
Carbohydrates are the macro-molecules made up of carbon, hydrogen, and oxygen.
Polymers of the carbohydrates (such as glycogen, starch) are made up of repeating units of monosaccharides such as glucose.
They are used as the short-term energy storage in most of the animals.
Glycogen is the polymer of glucose stored in the muscle cells and are used as the short term energy storage.
Our body can convert excess carbohydrates or food into the fat which is used for long-term energy storage.
In plants, starch (the polymer of glucose) is used as the storage form of the glucose or energy.