Develop two other plans for the Mexican roofing manufacturer described in Examples 1 to 4 (pages 572–576) and Solved Problem 13.1 (page 588).

a) For Plan 5, use constant workforce of eight workers for the first 3 months and ten workers for the last 3 months. Use subcontracting to meet the remainder of demand.

b) For Plan 6, use a constant workforce of nine. Use subcontracting to meet the remainder of demand.

c) Out of 1–6, which plan is the best and why?