1. I personally think voiding errors or mistakes of students may make the students to be not noisy and the teacher finishes the lecture without headache but it would definitely affect the those students who made the mistakes and even others cause they will lose their courage to participate again, by the passing of the time they may wouldn't even participate again and be completely loose and careless.
2. I think teachers mostly use all the ways depending on the situations but for me teacher D was the better than other ones cause personally i have tried that way many times which i spend the end of the lectures to correct their mistakes and answer their questions.