Certified Ethical Hacker (CEH) v13 312-50v13 — Question 222

An ethical hacker is preparing to scan a network to identify live systems. To increase the efficiency and accuracy of his scans, he is considering several different host discovery techniques. He expects several unused IP addresses at any given time, specifically within the private address range of the LAN, but he also anticipates the presence of restrictive firewalls that may conceal active devices. Which scanning method would be most effective in this situation?