Answer
Please see the work below.
Work Step by Step
We know that
a. Elements of group IIA and group VIIIA don't form negative ions hence they have electrons affinities greater than zero.
b. The difference between the second and the third ionization energies shows that would be a group IIA element.
c. Luster and conductivity are the properties of metals and group IIA is the only main group that contains only metals.
