The reaction if a lewis acid with a lewis base would most likely be accompanied by an increase in which item

covalent bonds
hydronium ions
electron pairs
hydroxide ions

A lewis acid is any substance which has the ability to accept nonbonding electron pairs and a lewis base is any substance that donates electron pairs. Therefore, if the two substances were to react, then the donation of electrons will result in the formation of covalent bonds. Thus, the reaction between a lewis acid and a lewis base is likely to be accompanied by an increase in covalent bonds.

Hydronium ions is the answer