[单选] You are the Cisco Network Designer in Cisco.com. Which of these is a Layer 2 transport architecture that provides packet-based transmission optimized for data based on a dual ringtopology？（）
A . Dynamic Trunking Protocol B . Resilient Packet Ring C . Synchronous Digital Hierarchy D . Coarse Wave Division Multiplexing
民事争议有什么特征？民事争议具有以下特征：
苯丙氨酸代谢途径关系到三种遗传病不包括下列哪种（） 黑酸症。 化病。 丙酮尿症。 血病。
审美体验是神秘、不可知的。
浮游相
美育和德育是两种不同的教育形式，二者没有什么联系。
You are the Cisco Network Designer in Cisco.com. Which of these is a Layer 2 transport architecture that provides packet-based transmission optimized for data based on a dual ringtopology？（）
