**3.5 Step 5: Developing the prototype multi-tier instrument**

A significant number of students should demonstrate students' unscientific understanding used as a reason option. Students' responses in this step are also used to measure the MCQ-FR quality in terms of validity, reliability, distractor effectiveness, discriminatory index, and difficulty level. The unscientific understanding above is utilized as the optional reason at the multi-tier instrument (**Figure 6**, Reason B).
