A is the thing that an organization does best--something that draws customers to the company, is difficult to imitate, and opens up potential markets.

core competence

Explanation:

Core competence Is often become a source of company's reputation in the market. It's the positive values possessed by the company that are very well known among customers.

For example,

When you heard the word 'McDonalds', most people will directly associate that word with delicious and affordable fast food. people recognize that company can provide that type of food really well. Better than most competitors in the market.

Similar effect can be found when people hear the word 'Google', They will associate it with the best search engine in the world. They might have other products, but search engine is considered as their core competence.