Greta has an idea for a new product. She wants to market outdoor holiday LED lights that can change their colors so that consumers can hang them outside year$-$round and alter the colors of the lights to match the season: multicolor for Christmas or blue and white for Hanukkah, orange and black for Halloween, and pastel colors for Easter. Because she wants such a product herself, she believes that others will want such a product as well. She thinks she has the financial resources to develop and market the product. In order to develop the product, what should her next step be$?$

a$.$ Concept testing

b$.$ Technical development

c$.$ Test marketing

d$.$ Idea generation

e$.$ Screening