在强酸性溶液中，能大量共存的离子是

A．Ca²⁺、K⁺、HCO₃^—、OH^—           B．Fe²⁺、Cl^—、H⁺、Na⁺

C．Fe²⁺、Mg²⁺、Cl^—、OH^—                      D．Ba²⁺、NH₄⁺、SO₄^2—、Cl^—

We are enclosing a full set of copy documents ______this first consignment

A. referring 

B. covering 

C. regarding to 

D. as for