The correct answer is C. The national anthem will be sung by one of the girls in the class at the end of the function.
A is incorrect because it does not specify that the girl will sing the national anthem at the end of the function. B is incorrect because it does not specify that the girl will sing the national anthem. D is incorrect because it does not specify that the girl will sing the national anthem at the end of the function.
The sentence “One of the girls in the class will sing the national anthem at the end of the function” can be paraphrased as “At the end of the function, one of the girls in the class will sing the national anthem.” This means that the girl will sing the national anthem at the end of the function, and that she is one of the girls in the class.