Which of the following is generally not considered as a barrier to entry?

Strong brand preferences and high degrees of customer loyalty to existing brands

The cost advantages enjoyed by industry members due to such factors as scale economies, learning$-$based

cost savings, partnerships with the best suppliers, ownership of key patents, and cost savings associated with

having valuable patents or proprietary technology

Tariffs and other international trade restrictions

The difficulties of building a network of distributors or retailers and securing adequate space on retailers'

shelves

Rapid market growth and weakly differentiated product offerings on the part of existing industry members