If the stock market is semi-strong form efficient, which should be the effect of a previously unanticipated announcement that a technology firm has developed a new and unexpected product with a positive net present value, in the absence of any other announcements or market moves: Group of answer choices The firm's stock price increases gradually to a new level. The firm's stock price immediately overshoots, then decreases to the correct level. The firm's stock price increases immediately to a new higher level. The firm's stock price immediately falls, then rises to its original level.