b$.$ Develop an aggregate plan using the same strategy from part a$,$ except that backlogs are allowed here. There should be no backlog remaining at the end of September. Hint: Use a maximum backlog of $5$ in any given month. You will need to develop a set of rules regarding which capacity option $($regular$,$ overtime, subcontracting$)$ is always preferable, and regarding the timing of these options $($i$.$e$.$ is it cost$-$effective to build ahead $($and thus carry inventory$)$ or to incur a backlog?$)($Round your Average values to $1$ decimal place. Negative amounts should be indicated by a minus sign. Leave no cells blank $-$ be certain to enter $"$O$"$ wherever required.$)$

Answer is complete but not entirely correct.