Consider a simple, non-paged memory management system in which memory consists of the following hole sizes in memory order: 10 MB, 4 MB, 20 MB, 18 MB, 7 MB, 9 MB, 12 MB, and 15 MB. Which hole is taken for successive segment requests of 12 MB, 10 MB, and 9 MB for (a) first fit (b) best fit (c) worst fit (d) next fit? Show all your work.