Suppose you have the short run production function estimated

Suppose you have the short run production function estimated to be:

Y= 100 L+ 50 L²- 3L³

^{a. At what number of workers does Stage III begin?}

^{b. At what number of workers does MPP reach its peak?}

^{c. At what number of workers will output be maximized?}

^{d. What level of output is the maximum?}