The standard that is supported by some Aruba APs and can enable a customer to accurately locate wireless client devices within a few meters is A) 802.11mc.
802.11mc is an IEEE standard that enables computing devices to measure the distance to nearby Wi-Fi access points using a technique called Fine Timing Measurement (FTM). FTM uses precise timestamps to calculate the round-trip time of Wi-Fi frames between the device and the access point, and then converts it to a distance estimate. By using multiple access points and triangulation methods, the device can determine its location with high accuracy1.
According to the Aruba document 802.11mc Support, this feature is supported on 500 Series, 510 Series, 530 Series, 550 Series, 560 Series and 570 Series access points. These APs act as FTM responders to time measurement queries sent from a client. To configure the AP to send FTM responses, you need to enable the ftm-responder-enable parameter in the WLAN SSID profile1.