A designed experiment is described.

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.

Identify the response variable measured.

Select one:

a. The treatment received (placebo, low dosage, high dosage)

b. Change in diastolic blood pressure

c. The dosage of the drug

d. The participants in the experiment

e. The one-month period