2*AB = 3*BC = 4*AC
Since the sum on angles in triangle is 180 then the ratio of degrees is 180/9 = 20
2*20:3*20:4*20 = 40:60:80
In order for all the angles of the triangle ABC be smaller than 90 degrees you cannot have a right angle. If you did then you could express the ratio of this triangle sides by the Pythagoras Theorem A^2+B^2 = C^2.
AC^2 + AB^2 = BC^2
Comply with Pythagoras Theorem. At least one angle is at 90 degrees.
the answer is (D)