Answer: b. accepts
ions from acids
Step-by-step explanation:
According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions
when dissolved in water and an acid is defined as a substance which donates hydronium ions
in water.
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates
ions and a base is defined as a substance which accepts
ions.

Here water is donating
ions, and thus act as acid and ammoia
is accepting
ions from water and thus is a base.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
Thus base is a substance which accepts
ions from acids.