Q$3.$ Identify if a system or a control volume should be selected for each of the following:

$($a$)$ A shock absorber $($see Figure $1)$

$($b$)$ The turbine in a dam

$($c$)$ Heating the water in a pressure cooker from cool water to just before boiling

$($d$)$ A piston$/$cylinder arrangement during the power stroke $($car engine$)$