In which of the following scenarios would an observational study be used instead of a survey or experiment? (1) a study to determine if people who have been vegetarian for that last five years have lower cholesterol than those who have eaten meat (2) a study to determine if adding sugar to water help plants grow faster (3) a study to determine if a new television show is watched by people called randomly on the phone (4) a study to determine if subjects who start a regular exercise routine lose more weight than those who start a low carbohydrate diet