Answer:
D. a more detailed sketch that covers materials.
Step-by-step explanation:
The design process typically involves several steps, starting with ideation and moving on to more detailed planning and execution. In this scenario, Manalo and Priya have already ideated and come up with a rough sketch of their idea for a portable air purifier. The next step in the design process would be to create a more detailed sketch that covers materials, as this would help them to better visualize and plan out the product's construction and manufacturing requirements. Only after this step is completed can they move forward to create a proposal for manufacturing the air purifier.