What statement about the IEEE 802.11e QoS facility is true?

Which one of the following channels can be used for VHT transmissions?

A WLAN is implemented using wireless controllers. The APs must locate the controllers when powered on and connected to the network. Which one of the following methods is commonly used to locate the controllers by the APs?

When using a spectrum to look for non Wi-Fi interference sources, you notice significant interference across the entire 2.4 GHz band (not on a few select frequencies) within the desktop area of a users workspace, but the interference disappears quickly after just 2 meters. What is the most likely cause of this interference?

ABC Company has just purchased a 6 dBi patch antenna. After performing some tests with the 6 dBi antenna, they have concluded that more antenna gain is needed to cover their outdoor courtyard. When choosing an antenna with higher gain, what other antenna characteristic will also always change?