If I received an inheritance in stock from a trust, the cost basis determined by: a) Cost of stock at purchase prior to receiving it b) Stock value on day of transfer

I received stock in-kind through a trust in Sept 2020, however my 1099-B shows the cost basis as when the stock was purchased in 2015, before I got it. I read that cost basis on inherited stock should be based on the stock value at time of inheritance disbursement. Which is correct?