Which of the following is to be placed at the peak of the 'curriculum triangle' while effecting a change?

A curriculum is the combination of instructional practices, learning experiences, and students' performance assessments that are designed to bring out and evaluate the target learning outcomes of a particular course. 

​Curriculum triangle

• The instructional objective change should be placed at the peak of the ‘curriculum triangle’
• As effecting a change as instructional decision directly affect the learning of the students.
• Then comes the Learning experiences change these changes affected by the choice of materials, pacing, and sequences of activities, to ways of reinforcing pupil's learning.
• After that comes Evaluation of learning outcomes which have means of assessing whatever the students have learned.

​therefore, option 1 is correct.