Auto-clear dependent dropdown when parent cell is changed

Hello!

I have created some dependent drop downs that only give certain options when an item from the first column is selected. I'm wondering if there is a way to auto-clear the subsequent columns if the first column is changed? I have looked around a bit and have seen some VBA code stuff, but I'm an inexperienced user so it is all greek to me. Is there a way to do this with a formula within a cell?

I've attached a sample. Please don't laugh at my crude attempts!

Thanks and I hope to hear from you soon!

Kim