Final answer:
In WLC QoS, the 'Best Effort' service is represented by the Bronze category. It is the default service level for applications that do not require guaranteed performance.
Step-by-step explanation:
In the context of WLC (Wireless LAN Controller) Quality of Service (QoS), the option that typically provides 'Best Effort' service is Bronze. This category is usually used as the default QoS level and does not provide any guaranteed throughput or delay specifications, which can also be seen as the lowest QoS level. It is intended for applications that can tolerate variable levels of delay and throughput such as web browsing or email.