Answer
Plot $VI$
Work Step by Step
Given: $x=(1-|u|)cosv$
$y=(1-|u|)sinv$ and $z=u$
To find the grid curves corresponding to $u$ as constant, substitute $u=k$
$x=(1-|k|)cosv$
$y=(1-|k|)sinv$ and $z=k$
This represents a family of circles parallel to $xy$ plane with radius $=1-|k|=1-|z|$
Only Plot $VI$ contains circular grid curves with radius $1-|z|$.
