Answer:
Option A
Explanation:
Given,
$x= a \cos t$
$y=a \sin t$
and z=t
Path is circular in xy-plane,
$\frac{x^{2}}{a^{2}}+\frac{y^{2}}{a^{2}}= \cos^{2} \theta+\sin^{2} \theta$
$\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}=1$
In one revolution, the particle moves a distance of unit along x-axis
$\frac{dz}{dt}=1$
Hence, the path is a helix