Answer:
The equation which has infinite many solutions is:
Option: C
C.

Explanation:
An equation is said to have infinite many solution if the equation holds true for infinite many values of y.
A)

On solving for the equation we have:

Hence, we get a unique solution.
B)

On solving this equation:

Hence, we get a unique solution.
C)

Hence, the equation is true for infinite many values of y.
Hence, the equation has infinite many solution.
D)

i.e.

Hence, again we get a unique solution.