Please answer this question.

Define the following terms. a. Observational study b. Designed experiment a. Choose the correct answer below. O A. In an observational study, researchers simply observe characteristics and take measurements, as in a sample survey. O B. In an observational study, researchers look at all the members of the group being studied. O C. In an observational study, researchers impose treatments and controls and then observe characteristics and take measurements. b. Choose the correct answer below. O A. In a designed experiment, researchers look at all the members of the group being studied. O B. In a designed experiment, researchers simply observe characteristics and take measurements, as in a sample survey. O C. In a designed experiment, researchers impose treatments and controls and then observe characteristics and take measurements