According to Bronsted-Lowry acid concept an acid is a that donate a proton" and a base is a "proton acceptor."so will look for that molecule to which <span><span>H2</span>O</span> "donates" <span>H+</span>to become <span>O<span>H−</span></span>. so answer will be.. . <span>N<span>H3</span>+<span>H2</span>O→N<span>H+4</span>+O<span>H<span>− so correct option is NH3 hope it helps</span></span></span>