The letters dmz stand for demarcation zone demilitarized zone defamation zone demineralized zone

The correct answer is the Demilitarized zone.

Explanation:                                                                                         In geopolitics when two or more nations are in a war conflict sometimes there is a neutral zone, as its name indicate, there are not soldiers, weapons, tanks and any like these, conversely, this zone is used for giving assistance to the civil population that is affected during war confrontation. As usual, these zones are located in the middle of the nations in a war to ease its access, this is called DMZ or demilitarized zone. This concept is also used in informatics, in which DMZ meaning or Demilitarized Zone refers to a net between a local net and external net with the objective of protecting the local net, this DMZ allows that the local net interacts with the external net but the external net does not access to the local net. Therefore DMZ stand for Demilitarized Zone.

he sent troops to protect the students as they entered the school.