Which one is the best reducing agent among alkali metal in aqueous solution ?(A) Li(B) Be(C) B(D) None of these

Among the options given, the best reducing agent among alkali metals in aqueous solution is option (A) Li (Lithium).

Lithium (Li) is the strongest reducing agent among the alkali metals because it has the lowest ionization energy and the highest electrode potential. This means that lithium atoms can easily lose electrons and form Li+ ions, which makes them good reducing agents in chemical reactions. In aqueous solutions, lithium can readily donate its electron(s) to other species, leading to reduction reactions.

Beryllium (Be) is not typically considered an alkali metal; it's an alkaline earth metal. While it can exhibit reducing properties, it is generally not as strong a reducing agent as lithium.

Option (C) "B" is not an alkali metal, and Option (D) "None of these" is not accurate, as lithium is indeed a strong reducing agent among alkali metals in aqueous solutions.