Assertion: Semiconductors are solids with conductivities in the intermediate range from ${10}^{-6}–{10}^{4}oh{m}^{-1}{m}^{-1}$.

Reason: Intermediate conductivity in semiconductors is due to partially filled valence bands

The correct option is C Assertion is a correct statement but reason is a wrong statement.

Analysing the assertion :

In Semiconductors conductivity depends upon the temperature. At normal temperature, they behave as insulators. But when temperature increases, the conductivity of the semiconductor increases.

Semiconductors are solids with conductivities in the intermediate range, between ${10}^{-6}and{10}^{4}oh{m}^{-1}{m}^{-1}$

So, the assertion is correct.

Analysing the reason :

The intermediate conductivity is due to the small energy gap between the valence and the conduction bands because there is no gap in the case of conductors and a very large gap in the case of insulators. It has a filled valence band.

So, the reason is a wrong statement.

Hence, the assertion is a correct statement, but the reason is a wrong statement.

So, option (C) is the correct answer.