Answer: The answer is (C) 1.25x + 0.5y =2.
Step-by-step explanation: One equation from the system of equations is given by
5x + 2y = 8.
We are to select the second equation such that the system will have an infinite number of solutions.
In such a case, we must have that the corresponding coefficients of 'x', 'y' and the constant term must be proportional.
We can see that for the equation 1.25x + 0.5y = 8,

Thus, (C) is the correct option.