A company just announced this morning that it has hired the world$$s most prolific and accomplished infectious disease researchers. Before today, the company$$s stock had been selling at $$200.$ Assuming there is no information in the coming week and the stock market as a whole does not move. What do you expect will happen to the company$$s stock? Consider the following scenarios:

The stock price jumps to $$225$ on the announcement day. In the following days, the price goes up to $$235$ and then falls back to $$220.$

The stock price jumps to $$215$ and stays at that level.

The stock price gradually climbs to $$220$ over the next week.

Which scenario$($s$)$ indicate market efficiency or inefficiency? Why?