Given:
The equations of system of equations are


To find:
The solution of given system of equations.
Solution:
We have,
...(i)
...(ii)
Adding y on both sides in (ii), we get


It is same as equation (i). So, we can say that equation (i) and (ii) represent the same line or they are coincident.
Thus, the system of equations has infinitely many solutions.
Therefore, the correct option is C.