What statement about 802.3, Clause 33 Power over Ethernet is true?

Which directional antenna types are commonly used by indoor Wi-Fi devices in a MIMO multiple spatial stream implementation?

The requirements for a WLAN you are installing state that it must support unidirectional delays of less than
150 ms and the signal strength at all receivers can be no lower than -67 dBm. What application is likely used that demands these requirements?

You are implementing a multi-AP WLAN and fast secure roaming is essential. Which one of the following methods is an IEEE 802.11 standard method for fast roaming?

A client STA must choose the best AP for connectivity. As part of the evaluation, it must verify compatible data rates. What can the client STA use to verify that an AP supports the same data rates that it supports?