Answer
Plot $II$
Work Step by Step
Given: $r(u,v)=sinvi+cosusin2vj+sinu sin2vk$
To find the grid curves corresponding to $v$ as constant, substitute $v=k$
$r(u,k)=sinki+cosusin2kj+sinu sin2kk$
This represents a family of circles which are parallel to the $yz$ plane
Only plot $II$ contains grid curves which are circles parallel to $yz$ plane.
