find the rate at which the temperate changes per unit change in the along the path r(t) at t=1.

Let the temperature 7 in degrees at the point (X , y, Z ), with distances measured in cm, be T(x,y,z)=x' -y + z', and let r(t) be a parametrization of a path in the plane such that r(1) = (2,3, -1) and r'(1) = (2,0, -1). Find the rate I at which temperature changes per unit change in t along the path r(t ) at t = 1. O none of the other answers Or= 10 Or= 5 Or= 26 Or= 21