Three Brands of AAA Batteries Are Compared to Determine If

Three brands of AAA batteries are compared to determine if differences in
Lifetime exist. Each brand is tested in four devices (TV remote, hand-held game,
Flashlight and digital camera) . The experiment is run once for each combination of brand
And device. The twelve runs are ordered randomly. The time (in minutes) that each
Battery lasts under continuous usage is recorded. Which of the following statements is
True about this design?

A) This is a completely randomized design in one factor.
B) The devices serve as blocks to account for the variability between the lengths of time batteries last in different devices.
C) The interaction effect between brand of battery and type of device is significant.
D) This is an observational study.
E) This is a retrospective study.