Let f (t) be the number of ducks in a lake t years after 1990. a. What does the statement f (6) = 31 mean? In 1996, there were 31 ducks in the lake. In 31 years, there will be 6 ducks in the lake. There will be 31 ducks in the lake 6 years from now. O In 1996, there were 31 more ducks than in 1990. b. What does the statement f (15) = 37 mean? In 37 years, there will be 15 ducks in the lake. In the year 2005, there were 37 ducks in the lake. Every 15 years, there are 37 more ducks in the lake. There will be 37 ducks in the lake 15 years from now