Testing is a critical phase in the Software Development Life Cycle $($SLDC$).$ It involves system testing as a whole where the complete and integrated software system is tested. The primary objective of system testing is to verify that the system meets the specified requirements and performs as expected in an environment that mirrors the real$-$world usage.

$($a$)$ Identify $3$ testing methodologies and describe their key characteristics.

$($b$)$ From your answer in question $($a$),$ critically analyze which methodology would you consider more effective in ensuring the system is ready for deployment. Justify your answer by considering the approach to verification of system requirements, outcomes, types of defects and contributions.