What is transferred between a conjugate acid-base pair?

a. an electron
b. a hydroxide ion
c. a hydrogen ion
d. a hydronium ion

C when conjugates are made they term the giving and taking of protons which in short hand for chemists means hydrogens. It is also the easiest way to tell which is what in an equation or just predicting a pairing if its an acid take away one proton you then have the conjugate base, when you look at a full equation look for what has an extra proton and which species is missing or in other words has a negative charge. The ones missing a proton is a conjugate base.