Final answer:
Subway franchise owners were upset with the $5 footlong promotion because it made them lose money due to the narrow profit margins. The cost of production and other fees made it unprofitable despite increased customer traffic.
Step-by-step explanation:
Subway franchise owners were primarily upset with the $5 footlong sub promotion because they lost money with the promotion. The cost of ingredients, coupled with labor, utilities, and royalty fees, often meant that selling the sandwich at this price point was not profitable. Many franchise owners expressed concerns that while the promotion drove traffic, the reduced margin impacted their profits significantly. The high volume of orders did not necessarily translate to higher overall profits due to these costs.
In contrast to options A and C, the franchise owners were not upset because they couldn't keep up with orders or because they desired an even cheaper sandwich. The concern was fundamentally about profitability and the viability of their businesses under the constraints of such a low-priced promotion.
It's notable that this situation underscores the complexities of promotional pricing in franchise operations, where the interests of individual franchisees and the franchise corporation can diverge. The corporation may benefit from increased brand visibility and sales volume, but individual franchisees bear the costs and may not reap the same level of benefits.