Below you are shown a product structure tree for end item A$.$ Weekly lead time values for purchase, manufacture, and assembly activities are shown to the immediate right of each item identifier. What is the minimum length planning horizon that should be considered for MRP production scheduling? You may need to use the scroll bar on the bottom of the page to see the entire diagram.

Question $6$Select one:

a$.$

$5$ weeks

b$.$

$23$ weeks

c$.$

$6$ weeks

d$.$

$4$ weeks

e$.$

$7$ weeks