Identify the Letter of the Choice That Best Matches the Phrase

Identify the letter of the choice that best matches the phrase or definition.
-A program that restricts access to specified websites.

A) digital signature
B) digital certificate
C) CA
D) digital security risk
E) firewall
F) botnet
G) zombie
H) clickjacking
I) Digital Millennium Copyright Act (DCMA)
J) DoS attack
K) AUP
L) iris recognition system
M) web filtering software
N) password
O) script kiddie
P) ciphertext
Q) plaintext
R) bot
S) piracy
T) copyright