Which of the following best describes the relationship between the two men

A．Smith gives Brown money.

B．Smith is faithful to Brown.

C．Brown’s noble character makes him faithful to Smith.

D．Brown is faithful to Smith because the latter often praises him.

混凝土设计坍落度为100-130mm时，允许偏差范围（）

A．±10mm 

B.±20mm 

C.±30mm 

D.±40mm