The blue "arrow" is

the distance traveled

the scalar

one of the component vectors

the resultant vector

The Resultant Vector

Explanation:

When two vectors are joined tail to tail and a parallelogram is completed in such a way that the resultant vector is always from common tail of the given vectors to the common head of two vectors.

So we have shown two vectors in this given diagram

red line is vector of velocity of airplane in forward direction which is of magnitude 150 km/h

while green line is another vector which is also another velocity

Now since these two vectors are connected tail to tail so the common diagonal here represented as resultant vector.

So correct answer is

Resultant Vector