Abel, a security professional, conducts penetration testing in his client organization to check for any security loopholes. He launched an attack on the DHCP servers by broadcasting forged DHCP requests and leased all the DHCP addresses available in the DHCP scope until the server could not issue any more IP addresses. This led to a DoS attack, and as a result, legitimate employees were unable to access the client's network.
Which of the following attacks did Abel perform in the above scenario?

A. Rogue DHCP server attack
B. VLAN hopping
C. STP attack
D. DHCP starvation