Layer 7 devices used to prevent specific types of html tags are called:
 
A.
 Firewalls
B.
 Content filters
C.
 Routers
D.
 NIDS
Explanation:
A content filter is a type of software designed to restrict or control the content a reader is authorized to access,
particularly when used to limit material delivered over the Internet via the Web, e-mail, or other means.
Because the user and the OSI layer interact directly with the content filter, it operates at Layer 7 of the OSImodel.http://en.wikipedia.org/wiki/Content-control_software#Types_of_filtering
http://en.wikipedia.org/wiki/OSI_model
 
                