OnEdit custum function for "task list" - if cell in collumn 3 is marked "x", text in collumn 2 should be striked through!

[Thomas Harnek]

So i already integrated a timestamp function in my TODO list, it works good.
What i wanted to add now is a function that will cross out the tasks that i 
mark as "done".

           A               B               C
1                    ̶C̶a̶l̶l̶ ̶J̶o̶h̶n̶           x
2                   Do Laundry    

So when i add an "x" in C2, B2 should be striked through.

Is that possible, and how could I do that ?

Hope for help
Thomas