When a new cellphone is put on the market, the demand each month can be described by the function C(t)= -√t^2+4t-12 +3, where C (t)
represents the demand of the cellphone (measured in millions of people) and the time, t, is measured in months. Which of the following
solution(s) are valid for a positive demand?
O a
Ob
Oc
Od
(7,0) and (3, 0)
(-6, 3) and (2, 3)
(6,3)
(2,3)