Where Two Parties Contract for the Purchase and Sale of an Ordinary

Where two parties contract for the purchase and sale of an ordinary item,such as a desk,that unknown to both parties is a rare and valuable example of that item,this is:

A) a unilateral mistake
B) a case of fraud in the inception
C) a mutual mistake of fact
D) a mistake of value,but not a mistake of fact
E) a case of fraud by concealment