Phil, a tax return preparer, charged his client $$500$ to prepare her income tax return that claimed a $$5,000$ refund based on an unreasonable position. To what penalty is Phil subject if Phil knew the position was unreasonable, but it was not determined to be the result of his willful and reckless conduct?

a$.$ $$250$

b$.$ $$500$

c$.$ $$1,000$

d$.$ $$5,000$