Correct option is A
Given:The torque developed in a squirrel cage induction motor with auto-starter.Starting torque (Tst), Full load torque (Tn), Starting current (Ist),Full load current (In), and full load slip (Sf).For an auto transformer starter, K represents the tapping of transformation ratio.Formula Used:For Direct Online Starter:TnTst=(InIst)2SfFor Auto Transformer Starter:TnTst=K2(InIst)2SfWhere:Tst→Starting torqueTn→Full load torqueIst→Starting currentIn→Full load currentSf→Full load slipK→Tapping of transformation ratioSolution:The torque developed in a squirrel cage induction motor with an auto-starter is K2×torque with direct switching, as per the formula for the Auto Transformer Starter.