שאלה | How is the AUC calculated in the ROC curve?

How is the AUC calculated in the ROC curve?

		By counting the total number of instances in the dataset
		By Ordering the instances according the “positive” class score/probability, iterating over instances, moving "up" for positive class instances and "right" for negative class instances
		By summing the true positive and false positive rates
		By computing the average of true positive and false positive rates for all instances.