The statement from the office of state School Education Minister, Anbil Mahesh Payyamozhi, said that all the 23 students who have opted for the examination are government school students. 

The state board had given an option to appear for the supplementary examination for students who felt that they did not get the marks they expected in the Class 12 board exam under the weightage system - which gave 50 per cent weightage to Class 10 marks, 20 per cent for Class 11, and 30 per cent for Class 12 internal assessment and practical marks. 

After declaring the Class 12 results, the Directorate of Government Examinations had provided the opportunity for aggrieved students to apply for the supplementary examinations. 

Payyamozhi, in the statement, said: "The School Education Department had announced that the students who are aggrieved with their marks under the weightage system, need to write the supplementary written exam in all subjects and the marks of this exam will be final." 

This may be the reason for most of the students to opt-out of the supplementary examination, he said. 

The supplementary examination for private candidates will be conducted from August 6 to 19, according to the statement. 

Several complaints are also coming up against the CBSE exam results with parents complaining that very low marks were awarded to students who had scored high marks in Class 10 examinations. 

Meanwhile, the Education Minister's office said that the government school teachers are directed to reach schools from August 2. Drawing flak over his announcement on reopening of schools, the minister had backtracked, stating that the government will take a decision to reopen schools after receiving reports from health experts.