Which factor is the best indicator of wireless client connection quality?

A. Downstream link rate, the connection rate for the AP to the client

B. The receive signal strength (RSS) of the client at the AP

C. Upstream link rate, the connection rate for the client to the AP

D. The channel utilization of the channel the client is using

Explanation:
SSI, or “Received Signal Strength Indicator,” is a measurement of how well your device can hear a signal from an access point or router. It’s a value that is useful for determining if you have enough signal to get a good wireless connection.

Reference: https://www.metageek.com/training/resources/understanding-rssi.html