One of the Biggest Problems Online Retailers Face Is

One of the biggest problems online retailers face is:

A) an inability to create time utility for the consumers who purchase through websites.
B) customers' tendencies to get to the checkout and leave the website without concluding the purchase.
C) its inability to allow comparison shopping when consumers are in a dilemma trying to choose between two or more products.
D) the difficulty of actually placing the online purchase.