Please explain in detail.

3. Consider the training and validation sets below. Table 1:Training: Table 2: Validation: a. Build a complete decision tree using the training data using GINI index. Show all calculations. (4 points: 3 points for calculations and 1 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 =0.5(1 points ) d. Compute the error rate of the tree using the validation set. (1 point)