The Irs is asking me to give them something to support 49 dollars on line 7 of my form 1040. I put in where it came from when i filed what else could i give them?

i did my taxes back in feb they are saying this 49 dollars is holding up my federal return. That if i don't give them a answer in 20 days they will either increase the tax i owe or reduce my refund.  It took almost 9 months to tell me this lol