Draw the concentration profile as a function of the reduced $($dimensionless$)$ residence time for tracer marking in the following reactor types:

$-$ a$)$ continuous ideal stirred tank reactor

$-$ b$)$ continuous real stirred tank reactor with bypass flow but without dead volume

$-$ c$)$ ideal plug flow reactor

$-$ d$)$ real plug flow reactor

Draw a$)$ and b$)$ as well as c$)$ and d$)$ for comparison in one diagram each. Label the curves.