Sequential Forward Search (SFS) algorithm has been used for feature selection. Suppose index 1 has been found to be the best feature among all the extracted features for three-category classification. Find out whether the combination of index 1 and index 2 or the combination of index 1 and index 3 is better to classify machine conditions into three categories. The obtained data are listed as follows: For the combination of index 1 and index 2 W: {(1,1)', (2,1)', (2,3)' (1,3)'} W: {(4,3), (5,3)', (5,4)' (4,4)'} W: {(6,5)', (8,5)', (8,7)' (6,7)'} For the combination of index 1 and index 3 W: {(1,1)', (2,1)', (2,2)' (1,2)'} W: {(4,4)', (5,4)', (5,6)' (4,6)'} W3: {(6,9)', (8,9)', (8,10)' (6,10)'} Please calculate the trace using the concept of intraclass Euclidean distance measures to justify your answer.