### Instruction: Find the curve defined by the equation
\[r = 2.\](A) Line
(B) Circle
(C) Parabola
(D) Ellipse
(E) Hyperbola

Enter the letter of the correct option.### Response: So we have $r=2$. What's $r$?
$r$ is the distance from the origin.
Right. So this is saying that the distance from the origin is 2.
That's a circle with radius 2.