A hierarchy of levels of learning is helpful in writing objectives because: a. they are written for cognitive, affective, and psychomotor areas
b. focus on a knowledge base
c. they suggest observable, measurable behaviors that may occur as the result of both simple and complex learning
d. all of the above

D

Explanation:

Hierarchy of learning objectives was given by Bloom. These include remembering, understanding, applying, analyzing, evaluating, creating.

The hierarchy is important as -

they are written for cognitive (mental), affective (emotional) , and psychomotor (phsyical skill based) areasfocus on knowledge base, by going through all levels (memory, understanding, reflective) levels of teachingthey suggest observable, measurable behaviors that may occur as the result of both simple and complex learning

So, for 'all of the above'