C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator where as Si is intrinsic semiconductor. This is because.

Question

( A ) The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
( B ) In case of C the conduction bans is partly filled even at absolute zero temperature
( C ) The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.
( D ) In case of C the valence band is not completely filled at absolute zero temperature.