What does acid do to the texture of egg whites ?

Acid delays coagulation, which means that there is more time for air to get trapped in amongst the proteins, resulting in a lighter meringue. The acids usually added to meringue are white wine vinegar, lemon juice, or cream of tartar. Fresh eggs are more acidic than old ones, so these help too

Explanation:

i think the answer could be either a or b because both are part of the post production part. hopefully this you a little.