During Which Phase and by Whom Should the Software Product

Multiple Choice

During which phase and by whom should the software product be tested for security,hacking,and proper functionality?

A) Testing happens during last phase of project and is done by the developers before releasing to the client.
B) Testing starts at the first phases of development and continues throughout by quality assurance testers.
C) Testing is started and completed during the design phase by the designers.
D) Testing starts at the first phases of development and continues throughout by developers and project managers.