During class, the teacher calls Mateo up to their desk to ask him a question while he is working on a project. Which of the following is the first thing Mateo should do before leaving his seat?
A. Ask a friend to make sure no one touches his computer.
B. Power his computer completely off.
C. Nothing; he's at school, so no one will play with his device.
D. Lock his computer so no one can access it.