The correct option is C a circle
Given the SHM equations in x and y directions are
x=acosωt ........(i)
y=asinωt ........(ii)
Squaring and adding equations (i) and (ii), we get
x2+y2=a2(cos2ωt+sin2ωt)
⇒x2+y2=a2
[∵cos2ωt+sin2ωt=1]
This is the equation of a circle of radius a with centre at the origin.
Hence, the trajectory of motion of the particle will be a circle.