The inductance of a power transmission line increases with

(A) decrease in line length.
(B) increase in conductor diameter.
(C) increase in spacing between phase conductors.
(D) increase in load current carried by conductors.

Answer: (C) increase in spacing between phase conductors.

Explanation: 

Inductance is directly proportional to the distance between the conductor. If we increase the spacing between the conductors then inductance will also increase.