Concept:Multilingualism as a strategy in teaching means using all the languages that learners already speak as a resource for learning.Explanation:Multilingualism is the ability to speak more than one language. In Indian classrooms, students come with different mother tongues. Instead of ignoring them, a creative teacher uses these languages as a tool. This helps in including every child regardless of their linguistic background. Students get to master their primary language and also learn others. Such a rich language environment improves thinking skills like observation, deduction, and reasoning. It leads to greater mental flexibility. Therefore, multilingualism as a strategy is about making use of the languages of the learners in teaching and learning.Answer:Option C – making use of the languages of learners.