You want the value at time t = 5. A payment at time t = 1 will be invested for 5 − 1 = 4 years.
And so on.
It might be easier to calculate the NPV, then compute the future value of that amount after 5 years. If you do that, make sure that you put in CF0 = 0.
Personally I always found it easier to draw out a timeline for questions like this to help keep things straight in my mind. The reason why the first year’s payment has an N of 4 applied to it is that you are calculating the future value here, not the present value (ie what the value of the t=1 cashflow is at t=5). The perspective here is that you are essentially sitting hypothetically at t=5 working out what the prior years’ cash flows are worth to you at that point in time. In this way, you need to know what the -2,000 cash flow is worth when compounded over 4 periods at 12% --> 2,000(1 + 0.12)4.
Hopefully that helps a little - can’t stress how useful drawing out the timelines really is. Once you get the hang of it they’re very quick to put together, and you’ll never get a question like this wrong again.