Suppose we have a callback function paint that is called every time the mouse is moved. Which version of paint will draw a circle at the mouse's location?
a) function paint() { drawCircle(mouse.x, mouse.y); }
b) function paint() { drawCircle(event.clientX, event.clientY); }
c) function paint() { drawCircle(this.mouse.x, this.mouse.y); }
d) function paint() { drawCircle(this.clientX, this.clientY); }