Consider the functions t(ac) = 2x+b rta q(a) = 2 v(a) (arta)(Etc) x2-b r(x) = abtxbtra+x2 where a, b, and c are natural numbers. Which of the following lists all of the functions which have no discontinuities and whose graph has a horizontal asmyptote at the x-axis? O both t(ac) and q(ac) Or(ac) Oboth r(a) and t(ac) Oq(x)