Electronegativity tends to decrease as atomic size increases and also tends to be lower in elements with fewer valence electrons. Therefore, among the options given, the element with the lowest electronegativity would likely be:
an element with a small number of valence electrons and a large atomic radius.
This is because elements with fewer valence electrons (typically metals) are less able to attract electrons, and larger atomic radius means that the valence electrons are further from the nucleus, reducing the effective nuclear charge felt by the valence electrons.