Denial of Service (DoS) is an attack on a computer or network that prevents legitimate use of its resources. In a DoS attack, attackers flood a victim system with non-legitimate service requests or traffic to overload its resources, which prevents it from performing intended tasks. Which of the following is a symptom of a DoS attack?
a. Unavailability of a particular website
b. Decrease in the amount of spam emails received
c. Automatic increase in network bandwidth
d. Automatic increase in network performance