A researcher wants to know if eating a mint affects whether people can distinguish between two popular orange juice brands. To conduct an experiment, the researcher places participants in two groups. The treatment group will eat a mint before drinking a juice, while the control group will not eat a mint before drinking. Then the participants will guess the juice brand.
 Randomization is important when assigning the participants to the treatment and control groups to ensure
 A that there will be the same number of participants in both groups.
 B that the experiment results can be generalized to all people.
 C that both groups have participants that like both popular juice brands.
 D that both groups are roughly equivalent with regards to demographics and juice preferences.