What is the difference in how revenue is recorded for wholesalers vs. retailers?

a) Wholesalers record revenue at the time of sale; retailers record revenue when goods are shipped
b) Retailers record revenue at the time of sale; wholesalers record revenue when goods are shipped
c) Wholesalers record revenue when goods are manufactured; retailers record revenue when goods are purchased
d) Retailers record revenue when goods are purchased; wholesalers record revenue when goods are manufactured