Patients who are addicted to cocaine are sometimes using the drug to combat depression. as such, sometimes addicts are given antidepressant medications to prevent relapse. a three-year study compared the effects of two such medication, lithium, and desipramine, along with a placebo for 72 cocaine users wishing to break the habit. the patients were put into 3 groups of 24, and given 1 of the 3 treatments at random. this two-way table illustrates the results. (picture shown)

among patients who did not relapse, which treatment was most effective, and what’s its conditional relative frequency?

a. lithium, at 6/24 = 25%
b. despiramine, at 14/72 = 19.44%
c. lithium, at 6/72 = 8.33%
d. desipramine, at 14/24 = 58.33%