Answer:
Options (A), (B)
Explanation:
Option A.
Two sides of the given triangle are equal. Therefore, the given triangle is an isosceles triangle.
Option (B).
Given triangle has a right angle. Therefore, it's a right triangle.
Option (C).
Only two sides of the given triangle are equal. Therefore, it's not an equilateral triangle.
Option (D).
Although this triangle has two acute angles (less than 90°) but the third angle is 90°. Therefore, this triangle is not an acute triangle. It's a right triangle.
Option (E).
A scalene triangle is a triangle having all sides different in measure but the given triangle is an isosceles triangle. Therefore, it's not a scalene.
Option (F).
Any angle of this triangle is not more than 90°. Therefore, the given triangle is not an obtuse triangle.