If `vec(x)` and `vec(y)` are two non-collinear vectors and ABC is a triangle with side lengths a,b and c satisfying `(20a-15b)vec(x)+(15b-12c)vec(y)+(12c-20a)(vec(x)xxvecy)=vec(0)` then triangle ABC is

Options

A. an acute-angled triangle
B. an obtuse-angled triangle
C. a right-angled triangle
D. an isosceles triangle

Answer

C