The group of elements that shows the least electronegativity among the options provided is:
C. alkali metals (1A)
Alkali metals, such as lithium, sodium, and potassium, have very low electronegativity values compared to other groups. Electronegativity generally increases across a period and decreases down a group in the periodic table. Alkali metals are found in Group 1, and their tendency to lose one electron makes them less electronegative.