In a semiconductor

A. there are no free electrons at any temperature
B. there are no free electrons at 0 K (zero Kelvin)
C. the number of free electrons is less than that in a conductor
D. the number of free electrons increases with temperature

Choose the correct answer from the options given below:

B, C and D only

The correct answer is Option (4) → B, C and D only

B. There are no free electrons at 0 K because the covalent bond are strong at absolute temperature.

C. In a conductor, free electrons are abundant, whereas in semiconductor, free electrons are relatively few.

D. It increase because thermal energy excites more electrons into the conduction band.