5 . The functional constraints of a linear model with nonnegative variables are 3 X 1 + 5 x 5 16 and 4X 1 + X 25 10 . Which of the following points could not be an optimal solution to the model ? a ) X 1 = 2.5 X 2 = 0 b ) X 1 0 X 2 3.2 ( ) X 1 1 X 2 2. 25 1 ) X 1 = 2 X 2 = 2