Concept:NEP 2020 encourages integrating sports into teaching to make learning engaging. Sports, including indigenous ones, can be effectively used in mathematics classrooms.Explanation:Statement (a) is correct: sports make the teaching-learning process joyful.Statement (b) is false: it is indeed possible to use sports for teaching math.Statement (c) is false: sports integration need not be time-consuming and should not be avoided.Statement (d) is correct: both popular and indigenous sports can be used to teach mathematics concepts.Therefore, only statements (a) and (d) are correct.Answer:D. (a) and (d)