The 760c form is for the Underpayment of Estimated Tax from the state of Virginia. This form is generated by TurboTax; it doesn't came to you in the mail.
Are you being asked about some amount on your 2019 760c? If so, please go look in your copy of your 2019 of form 760c.
If this doesn't help, then please come back and tell us.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"