15. the lagrangian for a three particle system is given by lhi+n+ne)-a"lii +ng-n -nn.) where a is real, then one of the normal co-ordinates has frequency o as (

15. The Lagrangian for a three particle system is given by Lhi+n+nE)-a"lii +ng-n -nn.) where a is real, then one of the normal co-ordinates has frequency o as (A)= a2 (B) -2a2 (C) 2 (D) =2 a2