Final answer:
The calorie is the unit of energy that's also used in slang to mean cool or great, with 1 calorie being equal to 4.184 joules. In scientific contexts, however, the SI unit of energy is the joule (J), where 1 cal is equivalent to 4.184 J.
Step-by-step explanation:
The unit of energy that has also been used in slang to mean cool, great, or wonderful is a) Calorie. In the context of energy, a calorie (cal) is the amount of energy required to raise the temperature of one gram of water by 1 degree Celsius. Calories are often used when talking about the energy content in food. The term 'calorie' can also be used in slang as a way to describe something as energetically positive. In scientific contexts, however, the SI unit of energy is the joule (J), where 1 cal is equivalent to 4.184 J.