The correct answer is D. Differential treatment meted out to students of his class.
An effective teacher is one who can create a positive learning environment, motivate students to learn, and help students achieve their academic goals. Effective teachers are also able to manage their classroom effectively and provide students with the support they need to succeed.
Emphasizing standards is important because it helps students understand what is expected of them and how they can improve their performance. Emphasizing group discussion for the purpose of clarifying the objectives is important because it allows students to share their ideas and perspectives, which can help them to better understand the material. Emphasizing the quick control of problematic situations is important because it helps to create a safe and orderly learning environment.
Differential treatment meted out to students of his class is not an effective teaching practice because it can create resentment among students and make it difficult for them to learn. Effective teachers treat all students fairly and provide them with the support they need to succeed.