The correct options are
A Acute angled triangle
D Obtuse angled triangle
On the basis of the angles triangles are divided into 3 types.
If the angles of a triangle are less than 90∘, then it is called an acute angled triangle.
If any one angle of a triangle is greater than 90∘ and less than 180∘, then it is called an obtuse angled triangle.
If any one angle of a triangle is equal to 90∘, then it is called a right angled triangle.