Which of the following activities are considered R&D? Justify your reasons for each answer.
1. Building an oil shale plant to test the feasibility of large-scale exploitation
2. Testing a new type of machine to evaluate its potential usefulness in production
3. Modifying a machine to make it suitable for filling a customer’s order
4. Designing a new plant to produce the same products more efficiently
5. Testing in an attempt to find a more efficient production method