Root competition among neighboring plants was studied by growing plants with their roots inside ...

Root competition among neighboring plants was studied by growing plants with their roots inside tubes of PVC pipes. Some tubes had holes of varying sizes, allowing their neighbors' roots to enter the tubes of a target plant. As the percentage of a target plant's tube open to neighbors' roots increased,
A) both target plant biomass and neighbor plant root biomass decreased.
B) target plant biomass decreased and neighbor plant root biomass increased.
C) target plant biomass increased and neighbor plant root biomass decreased.
D) both target plant biomass and neighbor plant root biomass increased.