Answer
plot $V$
Work Step by Step
Given : $x=(1-u)(3+cosv)cos4\pi u$
$y=(1-u)(3+cosv)sin 4\pi u$
$z=3u+(1-u)sinv$
To find the grid curves corresponding to $u$ as constant , substitute $v=k$
$x=(1-u)(3+cosk)cos4\pi u$
$y=(1-u)(3+cosk)sin 4\pi u$
$z=3u+(1-u)sink$
This is an equation of helix with a non- constant radius $=k$
Only plot $IV$ and $V$ contain grid curves which are helix.
But only plot $V$ contains helical grid curves with non-constant radius.
