The inductance of single phase two wire power transmission line per km gets doubled when the
(a) Distance between wires is doubled
(b) Distance between the wires is increased four fold
(c) Distance between the wires is increased as square of the original distance
(d) Radius of the wire is doubled
(a) Distance between wires is doubled
(b) Distance between the wires is increased four fold
(c) Distance between the wires is increased as square of the original distance
(d) Radius of the wire is doubled