# What is the standard form of the equation of a circle with r = 3; (h, k) = (0, 0 )?

${x}^{2} + {y}^{2} = 9$
${\left(x - h\right)}^{2} + {\left(y - k\right)}^{2} = {r}^{2}$
${\left(x - 0\right)}^{2} + {\left(y - 0\right)}^{2} = {3}^{2}$