In a triangle, tan(A)+tan(B)+tan(C) is equal to which of the following-

a)1

b)0

c)infinite

d)tanA+tanB+tanC

I am guessing the last option is actually tanAtanBtanC so I will prove that

as A,B,C are angles of a triangle
A+B+C = 180
thus


now computing the sum of the three tangents


which results into
Hence Proved