Books Ltd$.,$ a highly liquid traded, large and widely followed by analysts company trades on the Shelf Exchange. Two days ago, at $17$:$00,$ after the closing of the markets, its shares traded at $$15$ apiece. At the same time, the company issued a statement and sent out a press release indicating that the company expects to make a somewhat unexpected loss in the current financial year. Yesterday, the share price remained at $$15$ and today it is still at $$15.$

There were no other major macro$-$economic, market related or company specific developments that would have affected the company and the market was mostly flat over the day. are they..

a$.$Perfectly efficient

b$.$Somewhat efficient

c$.$Inefficient