ANSWER and EXPLANATION
We want to find out what scenario in real life can be represented by the integer -21.
The easiest and most relatable scenarios in real life that involve negative numbers has to do with money.
For money to be represented as a negative integer, it could mean that the person involved is owing another person/organisation.
For example, if I borrow $21 dollars from a friend so as to buy an item, then it means that at that moment in time, I have -$21, because I owe somebody $21.
Another example is temperature.
Temperature are often negative values e.g. -5°C, -40°F