The correct answer among the choices would be:
D. Fluorine (F)
Among all the elements, fluorine is the most electronegative element. Electronegativity refers to the measure of tendency of an electron to be attracted to that element. Since Fluorine is very electronegative, it can easily absorb the electrons of other elements. Since it sucks up electron, this gives Fluorine an excess electron thus making it a negative ion F-.