subassemblies as indicated. The total lead time, with no inventory on hand or in

process, is fixed at $8$ periods.

a$)$ If the current date is the beginning of Period $1$ and the customer request date is

Period $10,$ the latest release of Parts $D$ and $2$ must occur

$($A$)$ in Periods I and $2,$ respectively

$($B$)$ in Periods $2$ and $3,$ respectively

$($C$)$ in Periods $3$ and $4,$ respectively

$($D$)$ after Period $4$