What does "A" represent?

(1.) Ural Mountains ?
(2.) Mediterranean Sea ?
(3.) Pyrenees ?
(4.) Danube River ?
(5.) Iberian Peninsula ?
(6.) European Plain ?
(7.) English Channel ?
(8.) the Alps ?
(9.) Rhine River ?

What does A represent 1 Ural Mountains 2 Mediterranean Sea 3 Pyrenees 4 Danube River 5 Iberian Peninsula 6 European Plain 7 English Channel 8 the Alps 9 Rhine R class=