Brian is expanding his shop to include antique goods. What should he do if there isn’t a unique product identifier available?

Q) Brian is expanding his shop to include antique goods. What should he do if there isn’t a unique product identifier available?
Ans:

a) Include the word “antique” in the titles of all products
b) Leave all unique product identifiers blank
c) Use the exemption attribute ‘identifier exists’

d) Add ‘unique’ to the ‘brand’ attribute