We learned that in a medical/health application, a 'positive' class is considered more important and should have a higher misclassification cost than a 'negative' class. Which of the following methods can be used to take this cost consideration into account? a. Under-sampling for the records with a 'negative' class. b. Over-sampling for the records with a 'positive' class. c. Assigning a weight to each record based on the cost of corresponding class. d. All of the above.