Step 1: Concept
Heisenberg's Uncertainty Principle states it is impossible to determine simultaneously the exact position and momentum of an electron.
Step 2: Meaning
Mathematically, $\Delta x \cdot \Delta p \geq \frac{h}{4\pi}$.
Step 3: Analysis
The relationship defines the product of uncertainties as a value related to a constant.
Step 4: Conclusion
Hence, correct answer is Heisenberg's principle.
Final Answer: (C)