The correct option is
A acosα+bcosβ+ccosγFrom figure
In △OLA; cosα=ALa and cotα=ALx
⇒AL=acosα=xcotα ....(1)
In △OMB; cosβ=BMb and cotβ=AMy
⇒BM=bcosβ=xcotβ ...(2)
In △ONC; cosγ=CNc and cotγ=CNz
⇒CN=ccosγ=zcotγ ...(3)
From (1),(2) and (3)
AL+BM+CN=acosα+bcosβ+ccosγ