#### Answer

A: $(3,0,5)$
B: $(3,4,0)$
C: $(0,4,5)$

#### Work Step by Step

The vertex given is $(3,4,5)$, where $x=3$, $y=4$, and $z=5$.
A is on the $xz$-plane, so the $y$ coordinate is zero. Thus, A is at $(3,0,5)$.
B is on the $xy$-plane, so the $z$ coordinate is zero. Thus, B is at $(3,4,0)$.
C is on the $yz$-plane, so the $x$ coordinate is zero. Thus, C is at $(0,4,5)$.