Which one of the following would have been most effective in preventing this?

You are the Security Consultant advising a company on security methods. This is a highly secure location that deals with sensitive national defense related data. They are very concerned about physical security as they had a breach last month. In that breach an individual had simply grabbed a laptop and ran out of the building.

Which one of the following would have been most effective in preventing this?
A . Not using laptops.
B . Keeping all doors locked with a guard.
C . Using a man-trap.
D . A sign in log.

Answer: C