Selection that Enables/Disables other sections

Hi everyone,

I've been trying to wrap my head around this one but cannot figure out if the task is possible or not. I'm trying to create a form that has 3 sections. Update: I managed to use JavaScript to Show/Hide fields depending on the radio button selected, but am wondering if there is a way to clear and gray the fields depending on the selection.

My form has 3 sections. Section A, Section B, Section C. I want a user to be able to select which section they will to fill in and upon selection, the form will only allow the section they have selected to be filled in. If they select "Section A", then they cannot fill in "Section B" or "C". If they change their mind and select B or C, it would remove the entries in Section A and only let them fill in either B or C. 

I have included a link to the PDF I am trying to figure out as I assume a visual reference may be easier to follow.

Is there a way to achieve this? I am using Acrobat Pro. I would really appreciate any help... thanks so much in advance.

My Form