What is a lingua franca?

A lingua franca is indeed defined as a common language that facilitates communication between speakers of different native languages. The concept arises in contexts where diverse linguistic groups need to interact for trade, diplomacy, or other forms of social exchange. The use of a lingua franca allows individuals who do not share a mother tongue to engage with one another effectively, making it crucial in multicultural and multilingual environments.

Historically, languages such as trade languages or pidgins serve this purpose, allowing people from various linguistic backgrounds to communicate. A modern example is English, which has become a global lingua franca, especially in business, science, and technology. Therefore, choice C accurately captures the essence of what a lingua franca represents in linguistic and social interactions.