In recent years, the economy of our country____________ rapidly.   [ ]

A. is increased        

B. has increased      

C. increased            

D. has been increased

满月婴儿，母乳喂养，家人要求补钙，你认为下列哪项最合适()

A．母乳喂养儿不需补充维生素D和钙剂

B．应口服补充维生素D400IU/d

C．应口服元素钙200mg/d

D．添加辅食，不需补钙

E．应补充维生素D800IU/d，连续4周