Visit the official website, ctet.nic.in. Click on the ‘CTET answer key challenge’. Login using enter roll number and date of birth. Select the question to be challenged from the dropdown menu. Click on the ‘Select for challenge’ button. Click on the ‘Click to enter your answer’ link. Select the correct answer option against the selected question. Click on the ‘Update’ link. Click on the ‘Finalise challenges submission’ button and pay the fee.