Final answer:
Customers, employees, and competitors are considered to be the best source of new ideas for a business through their feedback and suggestions. Hence, 1), 2) and 3) are correct.
Step-by-step explanation:
The best source of new ideas for a business through their feedback and suggestions would be Customers, Employees, and Competitors.
Customers can provide valuable insights on what products or services they need or want, allowing businesses to innovate and improve their offerings.
Employees are on the front lines of a business and often have firsthand knowledge of areas that need improvement or ideas for new initiatives.
Competitors can also provide inspiration for new ideas as businesses analyze their strategies and learn from their successes and failures.