A security guard has informed the Chief Information Security Officer that a person with a tablet has been walking around the building. The guard also noticed strange white markings in different…

Jamming involves intentionally disrupting wireless signals by overwhelming them with noise or interference, which does not involve marking physical locations or mapping networks.

War chalking is the act of drawing symbols in public places to advertise the presence and details of open Wi-Fi networks, typically discovered through war driving or war walking. The person with the tablet is likely performing war walking to detect Wi-Fi networks, and the white markings in the parking lot are the method of communicating findings, fitting the description of war chalking.

Packet sniffing is the passive interception and analysis of data packets traveling over a network, and while a tablet could be used, it does not explain the physical white markings in a parking lot.

Near field communication (NFC) is a short-range wireless technology for data exchange between devices in close proximity (typically a few centimeters) and is unrelated to mapping Wi-Fi networks or leaving physical markings.