The 2010 FIFA World Cup in South Africa used 9 venues across 9 host cities: Cape Town, Durban, Johannesburg (2 stadiums), Bloemfontein, Nelson Mandela Bay/Port Elizabeth, Nelspruit, Polokwane, Rustenburg, and Mbombela/Nelspruit. However, the question asks for venues, which were stadiums. The Soccer City Stadium in Johannesburg was the primary venue. Among the options, 10 is the closest answer.