--- Lydia, what did our headteacher say just now?

--- Every boy and every girl as well as the teachers who       to lead the group

      asked to be at the school gate before 6:30 in the morning.

A．is; is

B．are; are

C．are; is

D．is; are

铸坯表面纵裂纹、横裂纹、网状裂纹均称之为缺陷（）。