Answer:
The correct answer is option A.
Step-by-step explanation:
According to the Bronsted-Lowry conjugate acid-base theory:
An acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.
For the given chemical equation:

Here,
is loosing a proton, thus it is considered as an acid and after losing a proton, it forms
which is a conjugate base.
And,
is gaining a proton, thus it is considered as a base and after gaining a proton, it forms
which is a conjugate acid.
Hence, the correct answer is option A.