3. Consider the training and validation sets below. Table 1:Training: Instance A B C Class 000+ 1 2 3 4 5 6 7 8 9 10 001 + 010 + 11 12 13 14 15 0 11 1 00 100+ 10 1 1 01 + 1 10 1 10 + Table 2: Validation: Instance A B C Class 000+ 011 + 1 10 101 1 00 a. Build a decision tree using the training data using the GINI index node. Show all calculations. (4.5 points: 4 points for calculations and 0.5 point for the decision tree) b. Compute the generalization error rate (using the training set) of the tree using the optimistic approach. (1 point) c. Compute the generalization error rate of the tree using the pessimistic approach, assuming that W = 0.25. (1 points) d. Compute the error rate of the decision tree using the validation set. (1 point)