What should be added to the setup, in the location indicated, for the unit test...

ApexPages.Standardcontroller sc = new ApexPages. Standardcontroller (acct.Id) ;

AccountControllerExt extension = new AccountControllerExt(sc) ;

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AccountControllerExt extension = new AccountControllerExt (acct);

ApexPages.StandardController sc = new ApexPages.StandardController(acct);

AccountcontrollerExt extension = new AccountControllerExt(sc);

AccountControllerExt extension = new AccountControllerExt (acct.Id) ;