(a) Universal indicator is a mixture of many different indicators which gives different colours at different $\mathrm{pH}$ values of the entire $\mathrm{pH}$ scale.
It shows different colours at different concentrations of hydrogen ions in a solution.
(b) Solution A gives pink colour when a drop of phenolphthalein indicator is added, therefore A is a base.
Solution B gives red colour when a drop of methyl orange is added to it, therefore $\mathit{B}$ is an acid.
Hence, solution A will have less concentration of hydrogen ion than $\mathit{B}$.
Thus, A will have $\mathrm{pH}$ more than 7 beause $\mathrm{pH}$ value of
(i) an acid solution
(ii) a base solution $>7$
(iii) a neutral solution $=7$
(c) (i) The salts of strong acids and weak bases give acidic solution having $\mathrm{pH}$ less than 7. Example, ${\mathrm{NH}}_4\mathrm{Cl}$, Ammonium Chloride will have $\mathrm{pH}$ less than 7.
(ii) The salts of weak acids and strong bases give basic solution having pH more than 7. Example, ${\mathrm{Na}}_2{\mathrm{CO}}_3$ Sodium Carbonate will have $\mathrm{pH}$ more than 7 .