Answer:
C.
A teacher put the names of students in a hat and pulled out 10.
Explanation:
All the other answers had some factor which would cause the answer to lean a certain way. For example, for answer D, Rebecca sent an email, which can be only sent using the internet, to ask how long people are on the internet. All the people that got the email probably use the internet longer than an average person does, making the answer, biased.