$1.$ Swapping $(20$ points$)$

Consider a swapping system in which memory consists of the following available

memory block sizes in the ascending order of memory addresses: $10$ KB$,4$ KB$,20$

KB$,18$ KB$,7$ KB$,9$ KB$,12$ KB$,$ and $15$ KB$.$ Which available memory blocks will be

allocated for the following three successive segment requests of

$($a$)12$ KB$,$

$($b$)10$ KB$,$ and

$($c$)9$ KB

with the policy of first fit? Now repeat the question for best fit, worst fit, and next fit.