Which one of the following is the most important person in the company? 1- Business Owner 2- Manager 3- Accountant 4- Salesperson 5- Customer

Any company starts with the Customer and ends with the Customer. 

customer

5- Customer

5 - customer

As it is said Customer is King of Market, Customer is Important amongst all of above. Without Customer you can't have business. Hence, there is no point of thingking beyond

All of them together in a nice cocktail.

The most important person to the company is customer! No customers = no livelihood of a company.

The most important person in a company is more difficult to answer. Important person in terms of what?

Setting up the company? Overall management? Insuring financial health of the company? Managing employees? Enforcing policies & strategies? Selling end product to customers? Generating vital revenues? You will agree that all of them are important, depending on business type.  

In my point of view option3&4

The manager

Because if the manager is good he can improve the company even the money is low

I think all are important but2 of them are imperatives. The manager and the customer.

The manager can rule the company being at the same time owner, accountant and sales man, and the customer can insure its solvability buying products and services.