Electrolysis involves oxidation and reduction respectively at

$O_2$ gas will be evolved as a product of electrolysis of $:$
$(A)$ an aqueous solution of $AgNO_3$ using silver electrodes.
$(B)$ an aqueous solution of $AgNO_3$ using platinum electrodes.
$(C)$ a dilute solution of $H_2 SO_4$ using platinum electrodes.
$(D)$ a high concentration solution of $H_2 SO_4$ using platinum electrodes.
Choose the correct answer from the options given below $:$

During the electrolysis of aqueous $NaCl$ solution, the product formed at the cathode is?

Which one of the following statements is correct for the electrolysis of brine solution?

The use of electrolysis is:

Which one of the following metals could not be obtained on electrolysis of aqueous solution of its salts?