Can't create bold text for 3 of 11 multiple choice - multiple selection questions

I have a multiple choice question with 11 options - multiple selection. I’ve managed to create bold text on 7 of the 11 options can’t seem to do so on the remaining 4? In order to bold the 7, I simply highlighted the text to bold and a pop up option to format (bold, italic or link) came up. I can’t get this to happen with the 4 remaining options