Answer:
Option A Concentration strategy
Explanation:
The reason is that the concentration strategy includes the complete focus of the company on a single product and to develop it further into a great product (Product development). For this the company invests its resources to ensure the product is desireable by the greater number of customers. So in this case the company is focusing to design and manufacture jewelry that alligns with its quality. The new product development is the type of product which is the focus of the company so the answer is Concentration, option A.