Answer:
test market the product among potential users.
Explanation:
In the context, it is given that a water purification device manufacturing company, H2 O'Yeah had designed a purification device which is far more better and efficient than any other water purification device currently present in the market.
The customer response about the design of the new purification device was also positive. But before going for mass production of the device, the company, H2 O'Yeah wanted to find out more about the customer 's response and so they are going to test market the device among the potential customers and will take their feedbacks and advices before full scale production.
It is an efficient way for a successful development of a product and knowing about the feedback about the customers.
Therefore the correct answer is "test market the product among potential users."