# Which of the following is incorrect:  When a potential difference is applied across, the current passing through
$\begin {array} {1 1} (A)\;An\: insulator\: at\: 0K \: is\: zero & \quad (B)\;A \: semiconductor \: at \: 0K \: is\: zero \\ (C)\;A\: metal\: at\: 0K\: is\: finite & \quad (D)\;A\: p-n\: diode \: at\: 300K\: is\: finite, \: if\: it\: is\: in\: reverse\: bias \end {array}$