A wireless engineer is designing a wireless network for a campus. Which two parameters can have a negative effect on the Wi-Fi coverage of an access point? (Choose two.)

Authentication type (WPA2, 802.1X, etc.) is a Layer 2 security mechanism and does not affect the RF signal strength or physical coverage area of the AP.

The surrounding area (physical obstacles like walls, floors, metal structures, and external RF interference sources) attenuates or blocks radio signals, directly reducing the effective coverage area of an AP.

While channel selection affects interference and throughput, the channel number itself does not directly shrink or expand the physical RF coverage footprint of the AP.

Wireless encryption (e.g., AES/TKIP) is a data-protection mechanism that operates at the frame level and has no impact on RF signal propagation or coverage range.

The type of antenna determines the radiation pattern (omnidirectional vs. directional) and gain, which directly controls how RF energy is distributed and how far the signal reaches in any given direction.