下列关于自然a（a>0）的式子中，值最大的是请选择ABCD3v;n*z;E0U,R)c5`-W4b;O:R/C0i:R(q;Z4P.V'k4M
A．a÷0.7/C0i:R(q;Z4P.V'k4M
B．a+0.7/C0i:R(q;Z4P.V'k4M
C．0.7÷a/C0i:R(q;Z4P.V'k4M
D．a÷0.7与a+0.7均有可能/C0i:R(q;Z4P.V'k4M