Answer:
Wormwood limited
Production plan that will yield the least cost of $49,630 is shown in the attached document.
It entails maxing out the regular capacity from period 1 to 5, and using regular to produce only 140 units in period 6
It further entails using overtime to produce 10 units from period 1 to 5. And subcontracting only in period 4 to cover the demand/production gap.
This will keep inventory of 10 units in period 2, which is carried into period 3 and consumed in period 4.