Multiple choice question:

When the FDA makes a public announcement that a major drug has been approved, the stock price of the company developing that drug generally increases on the announcement. Consider the following strategy: buy shares of pharmaceutical companies after the FDA approves a major drug from that company. Suppose this strategy generates zero alpha. Which of the following statements is most consistent with the above information?

i) The information is consistent with both strong form efficiency and semi-strong form efficiency.

ii) The information is consistent with strong form efficiency but not consistent with semi-strong form efficiency.

iii) The information is consistent with semi-strong form efficiency but not consistent with strong form efficiency.

iv)The information is not consistent with strong form efficiency and not consistent semi-strong form efficiency.

Please provide a short explanation for the correct answer.