In order to gain popularity among students, a new pizza place near school plans to offer a special promotion. The cost of a large pizza (in dollars) at the pizza place as a function of time (measured in days since February 10th) may be described as⎧9, 0 ≤ t ≤ 3C(t)= ⎨9+t, 3 < t ≤ 8⎩20, 8 < t < 28(Assume t only takes whole number values.) Write an expression that describes the sentence "The cost of a large pizza is at least A dollars B days into the promotion," using function notation and mathematical symbols only.