The correct answer is D. All of these.
In a cash flow diagram, time 0 is considered to be the present. This is because the cash flows are typically shown as arrows pointing to the right, with time increasing as you move to the right. So, the arrow at time 0 points to the right, indicating that the cash flow occurs at the present time.
Time 1 is considered to be the end of time period 1. This is because the cash flows are
typically shown as arrows pointing to the right, with time increasing as you move to the right. So, the arrow at time 1 points to the right, indicating that the cash flow occurs at the end of time period 1.A vertical arrow pointing up indicates a positive cash flow. This is because cash flows are typically shown as arrows, with positive cash flows pointing up and negative cash flows pointing down.
Therefore, the correct answer is D. All of these.