Mateo has a passion for collecting old watches. He's particularly interested in those from the 1920s because they have a history behind them.
He has learned that some of them are fake. Therefore, he takes the watches to an appraiser to ensure that they are genuine before he agrees to purchase them.
Mateo is concerned with the _____ of the watches.
a. periodicity
b. reliability
c. canonicity
d. authenticity
e. stability