A team of researchers was asked to study the extent of broadband access in Canada. It found some very old data online on broadband access from the start of 2001 to the end of 2003 and used it to construct the following quadratic model of the growth rate of broadband access: n(t) = 21-61+12 (3 points) (t is time in years; t = 0 represents the start of the year 2000) a) Determine the appropriate domain of the function n b) According to the model, when was the growth rate at a minimum? (3 points) c) Does the model predict a zero growth rate at any particular time? If so, when? (3 points) d) What feature of this quadratic model indicates that the growth rate eventually increases? (3 points)