Audio player not working for multiple choice questions

I have just migrated from version 3 to version 4 and right now the audio player is not working for multiple choice questions. It does work for fill-in-the-blank questions. I had hundreds of audio questions using the tags: [audio mp3="xxxxx"][/audio] However, with multiple choice question types, it shows the original code: http://prntscr.com/1w3ja5z With fill-in-the-blank type, the website shows the player: http://prntscr.com/1w3ji3w I tried changing one multiple-choice question to fill-in-the-blank type and the player showed again. So I guess with multiple choice questions, it doesn't recognize the tags <audio></audio>. I know there is an option to add audio files through the front end. Yet right now I have hundreds of questions from v3 with the tags <audio> and in the future I'm going to add more in bulk so it is not a wise choice to fix every question from the from the front end.