CompTIA Network+ N10-006 Q647

A network technician configures a firewall to block only certain IP addresses from accessing the Internet. All users are reporting that they are unable to access the Internet.
Which of the following is the MOST likely reason?

A. Incorrectly configured ACL
B. Implicit allow statement
C. SMTP requests are being denied
D. All protocols are being allowed in

Correct Answer: A