Which of the following has/have only two lines of symmetry?

A. Equilateral triangle

B. Rectangle

C. Rhombus

D. Isosceles triangle

Choose the correct option.

To find which of the given shapes have exactly two lines of symmetry, let's analyze the lines of symmetry for each shape one by one:

1. Equilateral triangle (A): An equilateral triangle has three equal sides and three equal angles. It has 3 lines of symmetry (each line passes through a vertex and the midpoint of the opposite side).

2. Rectangle (B): A rectangle has opposite sides equal and all angles equal to 90 degrees. It has 2 lines of symmetry (the lines connecting the midpoints of the opposite sides). The diagonals are not lines of symmetry because folding along a diagonal does not make the two halves match exactly.

3. Rhombus (C): A rhombus has all four sides equal. It has 2 lines of symmetry (along its two diagonals).

4. Isosceles triangle (D): An isosceles triangle has two equal sides. It has only 1 line of symmetry (the line passing through the vertex between the equal sides and the midpoint of the base).

Therefore, the shapes that have only two lines of symmetry are the Rectangle (B) and the Rhombus (C).

Thus, the correct option is B and C.