Which of the Following Studies Would Probably Require Written Informed

Multiple Choice

Which of the following studies would probably require written informed consent?

A) An observational study that measures walking speed of people entering and exiting buildings
B) An anonymous study that measures the relationship between time spent grocery shopping and money spent on groceries
C) A confidential study examining income level and voting behavior
D) An anonymous survey asking whether students want a coffeehouse opened in the library