DQ#$4-$ Designing the Application Components

Application components can come from existing components within the organization, purchased from outside suppliers, downloaded and installed as open$-$source software, or custom built in$-$house. How do developers decide which components should be purchased, obtained as open$-$source, or built in$-$house? How does the development team limit the alternatives? How do they decide on what the components could be and what alternatives are available for each component?