Assume all coffee comes from Dunkin Donuts, Starbucks, or Peets. Which of the following regressions most easily allows you to test whether Starbucks coffee has significantly more caffeine than all other coffees?
A. Caffeine = B0_hat + B1_hat*Starbucks + u_hat
B. Caffeine = B0_hat + B1_hatStarbucks + B2_hat Peets + u_hat
C. Caffeine = B0_hat + B1_hatStarbucks + B2_hat Dunkin+ u_hat
D. Caffeine = B0_hat + B1_hatStarbucks + B2_hat Peets + B3_hat*Dunkin + u_hat
Answer: A. Caffeine = B0_hat + B1_hat*Starbucks + u_hat