下列各组物质中，全部是弱电解质的一组是（　　）

A．MgCl₂  HClO  H₂S

B．SO₂  NH₃  CH₃COOH

C．NH₃•H₂O  H₂O  H₃PO₄

D．H₂SO₄  HNO₃  NaOH

________ there is going to be a policy change ________ of those things is going to change.[ ]

A．Unless; few  

B．Until; few

C．Unless; none  

D．Until; none