On choosing a different dropdown value than the previous one, I want the rest of the text boxes to become empty for me to fill in new values.

In a form, Suppose I have 3 values in my dropdown- A,B,C.  I have chosen A and filled the remaining text boxes accordingly, but I want to change the dropdown value to B. On changing i want the remaining values of the boxes to be empty so I can fill them again. How can I achieve this?