What does the speaker mean a. Mary sings the best in her grade. b. The speaker has no idea whether Mary sings well. c. Mary’s singing skills are inferior to a lot of her classmates. d. Mary’s singing skills rank the second in her class.

机动车行经人行横道应当减速行驶；遇行人正在通过人行横道，应当（）。

A.遵循“非机动车或行人让机动车的原则通行

B.快速抢道行驶

C.停车让行