Base is acceptor of

Explanation

In the context of the Bronsted-Lowry theory, a base is defined as a substance that accepts protons (H⁺ ions). Therefore, the correct answer is Option B: Proton. Option A is incorrect because OH⁻ ions are not accepted by bases; instead, bases can produce OH⁻ ions in aqueous solutions. Option C is incorrect as it refers to the Lewis definition of bases, which involves donating electron pairs, not accepting protons. Option D is incorrect because a base does not accept all of these, as it specifically accepts protons according to the Bronsted-Lowry definition.