Final answer:
Lack of physical store presence is not a central challenge for the online retail industry; it's part of the business model, while delivery delays, return inconveniences, and privacy concerns are actual challenges.
Step-by-step explanation:
Among the central challenges facing the online retail industry, lack of physical store presence is not considered one. This is because online retail inherently operates without physical stores, which is a fundamental aspect of the business model, rather than a challenge. However, delivery delays, inconvenience in returning goods, and consumer concerns about the privacy of personal information are genuine challenges that online retailers must address to ensure customer satisfaction and trust in the online shopping experience.