Addressing envelopes for a single parent with one child...

Quick question for you...

I have a couple of single parents with one child and I only have an outer envelope.

How do I address it?

Ms. Jane Smith and Son
Ms. Jane Smith and David
Ms. Jane Smith and Family

Anyone who can help, it would be greatly appreciated!

Thank you!

I'd write:

Mrs. Jane Smith
Master Daniel Smith (assuming the kid is under 10)