Consider the following two sets of equations :
I. 2x - y = 0 and 6x - 3y = 0
II. 3x - 4y = 0 and 12x - 20y = 0
Eqns. in I are 2x - y = 0 & 2x - y = 0
Thus, there is one equation in two variables.
.'. Given equations have an infinite number of solutions.
Eqns. in II are 3x - 4y = 0 & 3x - 5y = 0
Solving these equations, we get x = 0 & y = 0
So, (c) is true.