It is well known that knowledge is ____ treasure house, but practice is ___ key to it.

A．a; the

B．the; the

C．a; x

D．x; the

我国已经参加的有关驰名商标特殊保护的国际公约有（）

A.《巴黎公约》

B.马德里协定

C.商标注册条约

D.《关于保护驰名商标规定的联合建议》