Answer : The correct option is, Acids.
Explanation :
Acids : It is a type of molecule or an ion which has ability of donating or releasing a hydrogen ions or hydronium ions when dissolved in water.
Bases : It is a type of molecule or an ion which has ability of donating or releasing a hydroxide ions when dissolved in water.
Positive ions : It is formed by the lose of one or more electrons.
Salts : It contains two groups which are positively charged ion (hydrogen ion) and a negatively charged ion (hydroxide ion). That means the salt is produced when an acid combined with the base in the fixed proportions.
Hence, a substances that release hydrogen ions when dissolved in water are called acids.
