测定尿肾上腺素、儿茶酚胺时标本所用的防腐剂是（）

A.中性甲醛

B.浓盐酸

C.冰乙酸

D.麝香草酚

E.甲苯

The company is starting a new advertising campaign to ________new customers to its stores.

A．join

B．attract

C．stick

D．transfer