Which of the following represents correct order of conductivity in solids ?

Options

A. `K_("m eta Is") gtgt K_("in su lators") lt K_("sem icon du ctors")`
B. `K_("m eta Is") lt lt K_("in su lators") lt K_("sem icon du ctors")`
C. `K_("m eta Is") gt K_(" sem icondu ctors") gt K_("in su lators ")`= zero
D. `K_("m eta Is") lt K_("sem icon du ctors") gt K_("in su lators")ne `zero

Explanation

Correct order is, Metal `gtgt` Insulator due to energy gap between valence band and conduction band.