Refer to the cost curve in the following exhibit:
![443_784da610-3cc7-4e5b-bcdd-d2ca7dc1e295.png](https://secure.tutorsglobe.com/CMSImages/443_784da610-3cc7-4e5b-bcdd-d2ca7dc1e295.png)
a. What is the lowest level of output at which the efficient scale of production is reached in the long run?
b. In the short run described by SRATC, what is the efficient output level?
c. When the firm is producing at the level of output described by D, will it be experiencing constant returns to scale, economies of scale, or diseconomies of scale?