Respuesta :

Answer: S. (M,S)

Explanation:

Because if you have a Periodic Table you can see that:

S is {W in the periodic Table} (ᴇʟᴇᴍᴇɴᴛ- Tungsten) and

M is {Cr in the periodic table} (ᴇʟᴇᴍᴇɴᴛ- Chromium) they are both in the same group. Hope this helps. :))