Which of the following correctly shows how to add two vectors (adding the blue vector to the red vector)?

To add two vectors (blue vector to the red vector), follow these steps:

1. Draw the first vector (red vector) on a graph. The direction of the arrow shows the direction of the vector and the length of the arrow represents the magnitude of the vector.

2. Draw the second vector (blue vector) starting from the head (the pointy end) of the first vector. Again, the direction of the arrow shows the direction of the vector and the length of the arrow represents the magnitude of the vector.

3. The resultant vector (the sum of the two vectors) is the vector that starts from the tail (the end without the arrow) of the first vector and ends at the head of the second vector.

Please note that vector addition is commutative, meaning that the order in which vectors are added does not change the resultant vector. So, adding the blue vector to the red vector will give the same result as adding the red vector to the blue vector.