Within grid questions (multiple choice grid, checkbox grid, text response grid, dropdown grid, n-atrix, 3d matrix), variables (rows) can be set to hidden by default until they are triggered by a specific answer from a previous question.
Variables (rows) can also appear by default and be hidden if a respondent answers a previous question, or set of questions, in a specific manner.
First you will need to get to advanced branching by click on “Edit Survey Logic Rules” under the “Pages” tab. Once there, click on “Add Branching Logic” and set up your If statement. (Note: make sure your questions are assigned proper identifiers or it won’t work.) The If statement can be “If Question 1 variable 1 equals Choice 1.” For the then part, choose “Show a question” or “Hide a question”, like the picture above, then add the variable you want to show/hide and voila.
Alternatively, you can make separate questions to hide/disable. Check out the video below for more: