Option (1) is incorrect:Section 461 of theCode of Criminal Procedure deals with irregularities, which vitiate proceedings if the magistrate is not empowered to do so and to issue a search warrant under Section 94 of the CrPC by a magistrate, who is not authorised, does not come under this section.
Option (2) is incorrect: To hold an inquest under Section 176 of the CrPC does not come under Section 461.
Option (3) is correct: If a magistrate tries an offender summarily, who is not authorised to do so, will vitiate proceedings under Section 461.
Option (4) is incorrect: To tender a pardon under Section 306 of the CrPC does not come under Section 461.