A researcher is interested in whether caffeine influences participants' performance on different kinds of memory tests. The researcher randomly assigns participants to one of two conditions: caffeinated drink or a placebo (noncaffeinated) drink. The researchers also randomly assigns participants to an imagery-based memory test, an auditory-based memory test, or an implicit memory test. How many cells does this study have?

a. 2

b. 4

c. 8

d. 6