Save attribute of a UIButton

I need some help with my code.
I have an UIAlert that pops up the first time that you open the app, in that pop up I have two buttons and the user will choose one of those. I want the app to remember what button the user chose to execute some code or other. The thing is I have this code right here :

-(void)changeLabel{
 
 
         progressView.progress += 0.25;
     scan.hidden = YES;
 
 
         if (progressView.progress == 1 ) {
             label.hidden = YES;
 
             progressView.hidden = YES;
 
             [timer invalidate];
 
             imagesText.hidden = NO;
 
 
             int randomNumber = arc4random() % 4;
 
             switch (randomNumber) {
                 case 0:
 
 
                     imagesText.image = [UIImage imageNamed:@"image1.png"];
 
 
                     break;
 
                 case 1:
 
 
                     imagesText.image = [UIImage imageNamed:@"image2.png"];
 
 
                     break;
 
                 case 2:
 
                     imagesText.image = [UIImage imageNamed:@"image3.png"];
 
                     break;
                 case 3:
 
                     imagesText.image = [UIImage imageNamed:@"image4.png"];
 
                 default:
                     break;
 
         }
     }
 }
 

So I want to make it in some way that if the user selected the first button the app will do the switch between cases 0,1 and 2 and if he selected the second button it'll do it between 3 and others. But I want the beginning of the code to be the same for both cases.
I tried some stuff but it doesn't work how I wanted.
Thank you for your help!

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