What treatment is being compared to the control in the experiment?
a. The treated umbilical cord stem cells were cultured in the presence of an inhibitor from glioblastoma cells, but the control cells were cultured without the inhibitor.
b. The treated glioblastoma cells were cultured in the presence of an inhibitor from umbilical cord stem cells, but the control cells were cultured without the inhibitor.
c. The treated glioblastoma cells were stained with a fluorescent dye, but the control cells were not stained.
d. The control glioblastoma cells were run through the flow cytometer and then treated by being cultured in the presence of an inhibitor.
