Information:  - Liberia , officially the Republic of Liberia, is a country on the West African coast. Liberia means "Land of the Free" in Latin. It is bordered by Sierra Leone to its west, Guinea to its north and Ivory Coast to its east. It covers an area of and has a population of 4,503,000 people. English is the official language and over 20 indigenous languages are spoken, representing the numerous tribes who make up more than 95% of the population. The country's capital and largest city is Monrovia.  - The Sierra Leone Football Association is the governing body of football in Sierra Leone. It was founded in 1960, and affiliated to FIFA the same year. It organises and runs the national leagues, including the Sierra Leone National Premier League, Sierra Leonenan FA Cup, and the national football teams, including the under-17, under-20, under-23, and the senior national team. The Sierra Leone Football Association is made up of elected executive committee members, led by a president, who is currently Isha Johansen, who was elected in August 2013.  - The Sierra Leone national football team is the national team of the Republic of Sierra Leone was controlled by the Sierra Leone Football Association (SLFA), The team is affiliated to the West African Football Union of CAF and they have never qualified for the World Cup.  - Brookfields National Stadium is a multi-use national stadium of Sierra Leone , located in the capital city of Freetown . It is used mostly for football matches and it also has athletics facilities . It is the largest stadium in Sierra Leone and has a 45,000 capacity . The stadium serves as the exclusive home of the Sierra Leone national football team , as well as a venue for social , cultural , and religious events .  - West Africa, also called Western Africa and the West of Africa, is the westernmost subregion of Africa. West Africa has been defined as including 18 countries: Benin, Burkina Faso, the island nation of Cape Verde, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, the island of Saint Helena, Senegal, Sierra Leone, São Tomé and Príncipe and Togo.  - Sierra Leone, officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea on the north, Liberia in the south-east, and the Atlantic Ocean in the south-west. Sierra Leone has a tropical climate, with a diverse environment ranging from savannah to rainforests. Sierra Leone has a total area of and a population of 7,075,641 (based on 2015 national census).    Given the information above, choose from the list below the object entity that exhibits the relation 'operator' with the subject 'national stadium '.  Choices: - benin  - ivory coast  - nigeria  - sierra leone football association
A:
sierra leone football association