If $\overrightarrow{x}\text{ and }\overrightarrow{y}$  are two non-collinear vectors and a, b and c represent the sides of a triangle ABC satisfying $(\mathrm{a}-\mathrm{b})\overrightarrow{\mathrm{x}}+(\mathrm{b}-\mathrm{c})\overrightarrow{\mathrm{y}}+(\mathrm{c}-\mathrm{a})(\overrightarrow{\mathrm{x}}\times \overrightarrow{\mathrm{y}})=0$ then $∆$,ABC is(where $\overrightarrow{\mathrm{x}}\times \overrightarrow{\mathrm{y}}$ is perpendicular to the plane of $\overrightarrow{\mathrm{x}}\text{ and }\overrightarrow{\mathrm{y}}$)

• A

  an acute-angled triangle

• B

  an obtuse-angled triangle

• C

  a right-angled triangle

• D

  a scalene triangle