$\"\"$

The perimeter of the equilateral triangle is $\"\"$ .

Consider half of the equilateral triangle which is used as the diameter of the circle.

$\"\"$

Diameter of the circle , $\"\"$ is $\"\"$ .

Since it as a equilateral triangle each side of the triangle measuers $\"\"$ cms and the angle of each side is also $\"\"$ .

Since it is a right angle triangle $\"\"$ .

The circumference of the circle is $\"\"$ .

So, the circumference of the circle is $\"\"$ or $\"\"$ .

$\"\"$

The correct choice is B.