Which of the following should a teacher adopt in a lecture?

In a lecture a precise and high tone keeps the message both clear and audible to the whole class.

A precise but low tone is accurate yet may not reach the distant students.

An elongated tone drags the speech and dulls attention.

A moderate tone alone may lack the carrying power a lecture hall needs.

Clarity together with audibility makes oral delivery effective.

Pace, pause and modulation reinforce a well-pitched lecture.