Answer:
milk
Step-by-step explanation:
Gastric fluid is highly acidic with a pH of 1.5 -3.5 and very high [H⁺]. Milk has a pH of 6.5-6.7, so it has the lowest [H⁺]. Milk is only slightly acidic, it is very close to neutral pH of 7.0. Milk has lactic acid, which is a weak acid. Blood is neutral with pH of around 7.0, household lye is alkaline with a pH of 13.5. the higher the pH the lower the [H⁺] and vice versa.
pH = - log [H⁺]