Case Study Zero-Based Budgeting at Shell: https://www.strategy-business.com/article/11402

1. The article refers to a "substantial impact" on the company's cost budget; how significant was the expected reduction?
2. What aspects of the business were "off limits" during this exercise?
3. Describe what YOU think "cost creep" means and how it may arise?
4. How was the program first established?

Please give the explanation