The electron dot for cl

Well I'm guessing this is what you must mean

C.

Electron dot structure is related with the Lewis structure showing the valence electrons for a given element. In this case, the involved element is chlorine, whose symbol is Cl, which is located at the group VIIA, it means that it has seven valence electrons (the number of electrons at its outer shell) around it when expressing the aforesaid structure which is arranged as described on the C. option.