The correct answer is **Australia**. Pink Lake, also known as **Lake Hillier**, is located on **Middle Island in Western Australia**.

**Key Points for Study and Exams:**
- The lake is famous for its **natural pink color**, which is due to the presence of the **Dunaliella salina algae** and high salt concentration.
- It is a major **tourist attraction** and a frequent topic in **geography MCQs** and competitive exams.
- The lake retains its pink color even when water is taken out of it, which makes it scientifically fascinating.

Knowing unique natural landmarks like Pink Lake is important for **GK exams, quizzes, and interviews** where geographical superlatives are asked.