$\"\"$

The polar equation is $\"\"$ .

Transform the equation to rectanglular coordinates.

$\"\"$

Multiply on each side by $\"\"$ .

$\"\"$

Substitute $\"r$ and $\"\"$ .

$\"\"$

$\"\"$ .

The equation $\"\"$ is in the form of standard circle equation $\"\"$ with center $\"\"$ and $\"\"$ .

Therefore, the correct choice is option $\"\"$ .

$\"\"$

The correct choice is option $\"\"$ .