The most reactive metals are located at the a) top b) far-left c) far-right d) center of the periodic table.

It's at the bottom left of the periodic table

Bottom left corner of the periodic table

Explanation:

The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water, for example.