单项选择题
A. only Slots 6 or 12
B. only Slots 3 or 15
C. high or low speed slots
D. directly adjacent to the working card
E. high-speed slots only （5/6 and 12/13）
单项选择题 A customer has 20 E1s to add between far-end nodes in an SNCP ring. What type of circuit would you recommend？（）
单项选择题 Click the Exhibit button. As shown in the exhibit， a customer has several interconnected core rings. They want to create several irtual rings？utilizing their STM-64 backbone （nodes 1， 2， 3， and 4）. What do you recommend？ （）
单项选择题 A customer has 2 E1s to add between far-end nodes in an SNCP ring. What type of circuit should you recommend？ （）