Here are the answers to your questions:
Question Blank 1 of 3:
a. acids
Acids have a greater hydronium ion concentration (H+) and a lower hydroxide concentration (OH−).
Question Blank 2 of 3:
c. bases
Bases have a lower hydronium ion concentration and a greater hydroxide concentration.
Question Blank 3 of 3:
b. neutral substances
Neutral substances have equal amounts of hydronium and hydroxide.