Which statement best describes a bronsted-lowry base?
a) it must accept protons to form a conjugate base.
b) it must accept protons to form a conjugate acid.
c) it must donate protons to form a conjugate base.
d) it must donate protons to form a conjugate acid.

Option B

Bronsted-Lowry base is defined as an proton or hydrogen ion acceptor.

For example:

Here, is a Bronsted-Lowry base because it can accept proton or hydrogen ion from .

Acid forms conjugate base and base forms conjugate acid, since,  is a base thus, it forms   as conjugate acid.

Thus, a Bronsted Lowry base must accepts a proton to form conjugate acid and option B is correct.