设整型变量a,b,c已经声明，下列哪项语句的顺序是正确的？

A、cin>>a>>b; c=a+b; cout< <c;>
B、c=a+b; cin>>a>>b; cout< <c;>
C、cout< <c; c="a+b;" cin> >a>>b;
D、c=a+b; cout< <c; cin> >a>>b;