You’re is the correct answer, it stands for you are.
The correct option is C:<em> No country on Earth is immune from water shortages.</em>
Nowadays, water shortages are a worldwide problem. Not only South Africa or the United States, but also many other countries in the world suffer from water problems. In this way, a potential solution at local level could be not enough. It is necessary to take actions that revert this situation as soon as possible.
