A new-product department is excited about a new product idea for a suntan lotion that goes on blue, but fades away as the ability of the lotion to protect skin disappears. Projected sales, growth, and profit looked very promising. The idea has been passed to R&D to determine if the product could be feasibly made. At this point, the new-product department's idea is in the _____ stage.
marketing-strategy development
market testing
product-development
concept development
business analysis