Here is how to create 2 columns in mobile view.

Step 1: Go to the decision tree scripts as shown in the image below.

Step 2: Click on the “Add” button under the Decision Tree Scripts.

Step 3: Add the code below

  @media (max-width: 767px){
    .answer-col {
      margin-left: 0!important;
      margin-right: 0!important;
      width: 50%;
      float: left;

Step 4: Save and publish.