Which of these can be a valid graph?
Lets look at the options.
Option A →
This graph implies that at some instant t, the object has two displacements which is not possible.
Option B →
This implies that the object has negative distance which is not possible.
Option C →
Distance can never decrease with increase in time.
So option D is correct as distance always increases with time and at no single time the particle is having same distance.