D) All of the above.
Direct instruction is an effective method of instruction when teaching new concepts or skills because it typically involves all the elements mentioned:
A) The concept is clearly introduced and presented in a step-by-step manner, making it easier for students to understand.
B) The teacher ensures that students have the necessary prerequisite background knowledge to grasp the new concept, ensuring a strong foundation.
C) Students have opportunities to practice the modeled concept, typically through guided practice or exercises, before being expected to complete similar tasks independently, such as homework.
So, all these elements are part of effective direct instruction.