A steady current flows in a metallic conductor of non-uniform cross-section. The quantity/quantities constant along the length of the conductor are

Question

$\begin {array} {1 1} (A)\;Current, \: electric \: field \: and \:drift\: speed. & \quad (B)\;Drift\: speed\: only \\ (C)\;Current\: and\: drift\: speed\: only & \quad (D)\;Current\: only \end {array}$