I have just read chapters 5-8 in Criminal Evidence by Robert m. Donley, copyright 2018 by Pearson Education Inc.

2.How is the competence of a defendant determined?

I can't use any outside resources, only my textbook and the attached article called "Best evidence rule" by Cornell Law School

Reference

"Criminal Evidence" by Robert M. Donley Copyright 2018 by Pearson Education, Inc. All Rights Reserved.

https://www.law.cornell.edu/wex/best_evidence_rule