The Authors Recommend That Teachers Help Students Develop Their Listening

The authors recommend that teachers help students develop their listening skills by

A) speaking in very quiet voices at first, so students must strain to listen, before gradually increasing volume.
B) presenting all information nonverbally in an initial lesson, then gradually increasing the length of verbal utterances.
C) checking comprehension after very short learning activities, then gradually increasing the length of activities.
D) all of these.