What is the problem?

Refer to the network diagram and configuration shown in the graphic:

The network at the SOS Company has just been configured for NAT as shown. Initial tests indicate that everything is functioning as intended. However, it is found that a number of hosts cannot access the Internet. What is the problem?

A.
The access list is not correct.

B.
There are not enough IP addresses available in the NAT address pool.

C.
The wrong interface has been configured with the ip nat inside command.

D.
The IP address of the Fa0/0 interface is not usable.

E.
The S0/1 interface of the ISP router is in the wrong subnet.

Explanation:
The NAT POOL defined above only permits 5 hosts at a time. Because only 5 public IPs are available for NAT translation i.e only 5 hosts are translated because of one-to-one translation (private to public IP) and therefore remaining hosts are unable to access internet.
To overcome this problem use the NAT OVERLOAD or Port address translation.