I'll give you the train of thought, and you can analyze whether there are any mistakes.

First, the area of two triangles of OAB. One in the first quadrant and one in the third quadrant.

Then, when the vector 1 (forgive me for not typing that Greek) takes a negative value, the vector 2 takes a positive value, which is a triangle against the triangle OAB, with B as the vertex and the straight line where the coordinate axis (-2,0) is located as the bottom. (Poor eloquence, forgive me! )

Say it again, so it's d.