Explanation

PTI is correct because reports indicate that PTI leadership issued show cause notices to its MPAs regarding alleged vote selling. MQM is incorrect because there are no current reports suggesting this action by MQM. PML-N is incorrect because the question specifies a party issuing such notices in relation to recent Senate elections, and this was not reported for PML-N. JI is incorrect because there are no reports linking JI leadership to issuing such show cause notices.