Basic Number Classifier
Write a JavaScript function named `classifyNumber` that accepts one numerical argument (`num`). The function must return one of three strings based on the input: 1. Return "Positive" if `num` is greater than zero. 2. Return "Negative" if `num` is less than zero. 3. Return "Zero" if `num` is exactly zero. This exercise tests fundamental JavaScript concepts: function definition, parameter handling, and basic conditional logic (`if/else if/else`).