I think you can do it using Conditional Text. Select the answers and create a condition. And then you can choose to hide all the text with that condition.
Thanks Ellis home,
Because the conditional text impacts upon tabbed lines, I'll need to create two different conditional texts, one of just the lines, and the other of the answers. Unfortunately, there doesn't seem to be a way to apply conditional text as part of a style, which would enable me to set whole paragraphs as conditional at a time.
But in any case, it is the best solution available.
Another solution is to work with styles.
I had once the same problem. My solution was:
Create a style with letters with no color, only underline and for check boxes, I created 2 styles, one correct, one wrong, but both with a checkbox, looking identical. The checkbox was defined as bullet list.
Then I created an alternative layout (content is linked with new styles). In the alternative layout styles I changed the text color to something visible and the bullets were instead of a box an ok symbol and a false symbol.
Once created, this style could be reused every time.