Which of the following elements would most likely combine to form a salt

Metallic cations from groups IA and IIA with non-metallic anions from groups VIA and VIIA.

Explanation:

Hello,

In this case, since you are not providing the elements, I'm bestowing you a strategy to predict such formation. In this case, the pair of elements most likely to form a salt are those that have a large difference in their electronegativities, it means, elements far away considering the periodic table, say metallic cations from groups IA and IIA with non-metallic anions from groups VIA and VIIA. Take into account that noble gases cannot form any compound as they do not have valence electrons. For instance, some examples are NaF, KI, CsBr and others.

Best regards.

a is the correct answer