B
B. Self Reliant
As mentioned by the other folks, you can run 120 or 240 for lamps. The only difference is the number of amps you'll be drawing, which in most rooms means that if you're running 120 volts, then you'll have to put in extra outlets. If you use the 240 you can put them all on the same outlet.
Usually what dictates volts is what kind of outlets are already available, & what your ballasts are wired for. If you have a 240 circuit, and your ballasts are 240, then your choice has been made for you unless you enjoy extra work.
Smaller grows are different, but a 4k grow usually needs extra outlets and circuits in order to run that much power. You might luck out and find a 240 outlet somewhere other than a kitchen or garage, but most homes don't have too many of them.
Usually what dictates volts is what kind of outlets are already available, & what your ballasts are wired for. If you have a 240 circuit, and your ballasts are 240, then your choice has been made for you unless you enjoy extra work.
Smaller grows are different, but a 4k grow usually needs extra outlets and circuits in order to run that much power. You might luck out and find a 240 outlet somewhere other than a kitchen or garage, but most homes don't have too many of them.