Which Parametric Equations Describe a Circle with Its Center at the Origin

Multiple Choice

Which parametric equations describe a circle with its center at the origin and a radius of 7 for $0 \leq t \leq 2 \pi ?$

A) x=7 cos t and y=7 sin t
B) x=7 sin t and y=7 sin t
C) x=cos 7 t and y=sin 7 t
D) $x=\frac{1}{7} \cos t \text { and } y=\frac{1}{7} \sin t$
E) x=49 cos t and y=49 sin t