Step 1: Understanding the resistance of lamps.
For a given voltage, power is inversely proportional to resistance. Since \( P = \frac{V^2}{R} \), the 100 W lamp will have a lower resistance than the 60 W lamp.
Step 2: Explanation.
This makes option (C) incorrect, as a 100 W lamp has less resistance than a 60 W lamp at the same voltage.
Final Answer:
\[
\boxed{\text{C}}
\]