Potassiun nitrate salt is KNO3.
K is a metal, so it must come from the base, and NO3 is a radical that comes from an acid.
The acid with NO3 is nitric acid---> HNO3.
The base with K is potassium hydroxide ---> KOH
So the neutralization reaction is between nitric acid and potassium hydroxide.
HNO3 + KOH ---> KNO3 + H2O.
Answer: the nitric acid and the potassium hydroxide.