The length of a metal wire is `l_(1)` when the tension in it is `T_(1)` and is `l_(2)` when the tension is `T_(2)`. Then natural length of the wire is
A. `((l_(1)+l_(2)))/(2)`
B. `((l_(1)-l_(2)))/(2)`
C. `(l_(1)T_(2)-l_(2)T_(1))/(T_(2)-T_(1))`
D. `(l_(1)T_(2)+l_(2)T_(1))/(T_(2)+T_(1))`
