It's not (A), for that would be 



...
It's not (B), for that would be 


...
...
It's not (C), for that would be a "two-way" sequence that goes "left and right":
...









...
but that contains the undefined term "1/0". So that's not it.
If the following were listed I would pick this:
I would hesitate to pick (D) for it says nothing about n being and integer.
But I would also hesitate to pick (E)
However, after thinking about it, I would pick (D) after all because you are
given that it is an infinite sequence, so it would not be necessary to say that
n is an integer.
Edwin