释放还是自动释放?

我应该为varSecondViewController使用release还是autorelease?

-(IBAction)takeNextStep: (id) sender
{
    SecondViewController *varSecondViewController = [[SecondViewController alloc]     
       initWithNibName:@"SecondViewController" bundle:nil];
    [self.navigationController pushViewController:varSecondViewController animated:YES];
    [varSecondViewController release];
}