123. An electrical charge Q is placed at one vertex of an equilateral triangle. When an identical charge is placed at another vertex, each charge feels a force of 15 N . When a third charge identical to the first two, is placed at the third vertex, what would be the magnitude of the force on each charge?
(A) 15 N
(B) 26 N
(C) 30 N
(D) 42 N
(A) 15 N
(B) 26 N
(C) 30 N
(D) 42 N