Which of the following means of wireless authentication is easily vulnerable to spoofing?

MAC addresses are broadcast unencrypted in every 802.11 frame, so an attacker can use a wireless packet analyzer to capture a valid, authorized MAC address and then configure their own adapter to impersonate it. Because the access point only checks the hardware address and not a cryptographic credential, spoofing bypasses the control entirely.

WPA-LEAP uses a challenge-response mechanism and while it has known weaknesses to dictionary attacks, it is not specifically described as 'easily' spoofed in the same trivial sense as MAC addresses.

WPA-PEAP tunnels authentication inside TLS, providing strong mutual authentication that is not easily spoofed.

Enabling SSID broadcast makes the network discoverable but is a visibility setting, not an authentication mechanism, so it is not relevant to spoofing authentication.