A strip of pure silicon is warmed from room temperature to 100 °C while its resistance is monitored, and the resistance drops. Read the Assertion (A) and Reason (R) and choose the correct option.

• Assertion (A): The electrical conductivity of an intrinsic semiconductor increases as its temperature rises.
• Reason (R): Thermal energy breaks more covalent bonds, lifting electrons into the conduction band and creating an equal number of holes.