What is unseen cannot be seen

One of your associates is complaining that his Windows XP computer has been performing slower over the last few weeks. During that time, many new applications were installed on his computer. Which of these would be the best way to see all of the processes running on his computer?

A) Control Panel / Administrative Tools / Services

B) msconfig

C) Control Panel / Administrative Tools / Performance Monitor

D) Task Manager / Processes Tab and Services Tab

E) If you get a flashlight and peek into the ventilation slots, you can pick out the bits that are slowing down the rest of the computer.