Explanation:
A person who teaches in a school is commonly known as a teacher. Let's discuss why the correct answer is option 'B'.

Teachers:
Teachers play a crucial role in the education system. They are responsible for imparting knowledge, skills, and values to students in a school setting. Teachers work with students of different age groups and facilitate the learning process by delivering lessons, conducting activities, and assessing students' progress.

Role of a Teacher:
Teachers have various responsibilities and duties that contribute to the overall development of students. Some of the key roles of a teacher include:

1. Instruction: Teachers plan and deliver lessons to students, ensuring that they understand the concepts being taught. They use various teaching methods and resources to make the learning process engaging and effective.

2. Assessment: Teachers assess students' progress by evaluating their performance through tests, quizzes, assignments, and projects. They provide feedback and suggestions for improvement to help students enhance their knowledge and skills.

3. Mentorship: Teachers act as mentors and guide students in their academic and personal development. They provide support, advice, and encouragement to help students overcome challenges and reach their full potential.

4. Classroom Management: Teachers maintain discipline and order in the classroom, ensuring a conducive learning environment. They establish rules and routines, manage student behavior, and resolve conflicts if any arise.

5. Curriculum Development: Teachers participate in curriculum planning and development. They align their teaching with the prescribed curriculum and create lesson plans that cater to the diverse needs and abilities of their students.

6. Parent-Teacher Communication: Teachers regularly communicate with parents or guardians to provide updates on students' progress, discuss concerns, and collaborate in supporting their child's education.

7. Professional Development: Teachers engage in continuous professional development to enhance their teaching skills, stay updated with the latest educational practices, and adapt to changing educational trends.

In conclusion, a teacher is the correct answer because they are responsible for teaching and nurturing students in a school environment. Their role extends beyond just delivering lessons, as they also mentor, assess, manage classrooms, and collaborate with parents.