Drop Down dependent based on two dropdown ?

Hi @All,

I want to solution to dropdown Listing based on two parent dropdown condition 

scenario- i have 3 Drop Down 1-categeory 2-Subcategeory 3- application office

current fun-: subcategory dropdown list is shows based on category and application office list of dropdown shows on subcategory as per my current functionality.

but now i want application office Dropdown list of value based on both category and subcategory list of some values or conditions. 

  Thanks