Please help with this question. I have selected the following and it is coming out incorrect two separate times. Thank you.

1. a patent for a new car battery

2. increasing customer loyalty

QUESTION 1 All of the following are examples of barriers to entry that help a firm maintain monopoly power except for: O a patent for a new car battery 0 owning the only arena in the city limits 0 building a large factory with many high-priced machines 0 charging a high price and restricting the quantity produced 0 increasing customer loyalty to your product through advertising