Hello Vidya,
I'm happy to help! To modify text labels for the Correct and Incorrect banners, please click the Home tab in the Storyline ribbon and select Player, as shown below.
When the Player Properties window opens, click Text Labels and change the custom text for these items:
If the Correct and Incorrect banners are still not displayed correctly after the process above, the problem may be related to how the quiz question is set up.
Would you be willing to share your Storyline file with us so we can investigate the issue further? You may also share it privately by sending it along in a support case. We'll delete it when we're done testing.