A Drug Company Wanted to Test a New Indigestion Medication

A drug company wanted to test a new indigestion medication. The researchers found 400 adults aged 25-35and randomly assigned them to two groups. The first group received the new drug, while the second receiveda placebo. After one month of treatment, the percentage of each group whose indigestion symptoms decreasedwas recorded and compared. How many levels does the treatment in this experiment have?

A) 2 (medication or placebo)
B) 400 (number of respondents)
C) 1 (months of treatment)
D) 10 (age span of respondents)