The answer is National security because the citizens need to know that they are being protected, and usually also how they are being protected. But the government often needs so measure of secrecy in order to protect National Security. If the government were to tell citizens exactly how they were being protected and someone posted it onto the internet it would severely compromise that protection. However people do not generally seem to understand that and tensions become heated between the two groups. Both sides reasons are perfectly legitimate, but one outweighs the other by knowledge. The answer is B.