Which of these is a correct use of parallel structure?
A. We have to cut back these trees because they block the light, drop
leaves in the gutters, and look like they're dying.
B. Someone who cuts down trees has to be good at planning,
climbing, and have good balance.
C. Our company will remove dead branches, cut down unwanted
trees, and you can pay extra for us to clean up the mess.
D. One worker climbs the tree, the other holds the ropes, and a stump
grinding machine on the ground below.
