A certain short-day plant flowers only when days are less than 12 hours long. Which of the following would cause it to flower? a. a 9-hour night and 15-hour day with 1 minute of darkness after 7 hours b. an 8-hour day and 16-hour night with a flash of white light after 8 hours c. a 13-hour night and 11-hour day with 1 minute of darkness after 6 hours d. a 12-hour day and 12-hour night with a flash of red light after 6 hours