It’s B) null set i am pretty sure
Answer:
Acute, Obtuse and right angled triangle are the three triangles on the basis of angles.
Equilateral, Isosceles and Scalene are three triangles on the basis of of sides.
The seven types of triangles that exist in the world: equilateral, right isosceles, obtuse isosceles, acute isosceles, right scalene, obtuse scalene, and acute scalene.
