Which of the following is an example of a census?

A large retailer wants to determine the proportion of its customers who browse for merchandise online but make the final purchase in person at a store. At the time of purchase, each cashier is required to ask the customer whether the customer shopped online for the merchandise first.
A large retailer wants to determine the proportion of its customers who browse for merchandise online but make the final purchase in person at a store. At the time of purchase, each cashier is required to ask the customer whether the customer shopped online for the merchandise first.
To determine the median income of all working U.S. adults, a marketing firm conducts a national survey of 50,000 randomly selected individuals across all 50 states.
To determine the median income of all working U.S. adults, a marketing firm conducts a national survey of 50,000 randomly selected individuals across all 50 states.
Survey students about the college class schedule by randomly selecting 500 from the college's enrollment records.
Survey students about the college class schedule by randomly selecting 500 from the college's enrollment records.
To determine the proportion of the graduating class that is college ready, a local high school tests the reading comprehension of each 12th grader.