When Simple Semiconductors was operating at the minimum efficient scale of 10,000–12,000 units per month, the firm's cost per unit was $45. However, when the output level was increased beyond 12,000 units, the cost per unit increased to $47. This increase was attributed to the wear-and-tear of the machinery, and complexities of managing and coordinating. What is this phenomenon known as? a) minimum efficient scale
b) diseconomies of scale
c) experience curve effect
d) learning-curve effect