please help, I don't understand...

A building with an appraisal value of $139,335 is made available at an offer price of $152,441. The purchaser acquires the property for $31,211 in cash, a 90-day note payable for $20,709, and a mortgage amounting to $50,968. The cost basis recorded in the buyer's accounting records to recognize this purchase is Oa. $139,335 Ob. $121,230 Oc. $152,441 Od. $102,888