Increasing returns to scale

Posted by VanHelsing on Mar 15, 2018; 6:01pm
URL: http://discussion-forum.276.s1.nabble.com/Increasing-returns-to-scale-tp7608854.html

Can someone please help me with this question ?

If production function is such that there is IRS, then

a. Perfect competition is inconsistent.
b. Production wise efficient number of firms is 1.
c. P=LAC  at long run equilibrium
d. All of the ABOVE

Since there is IRS, I know both the LAC and LMC curves are downward sloping continuously, and the LMC is below the LAC always. This enables me to eliminate options c and d. But how to eliminate either of options a and b ?