Which property would cesium most likely have?
a. it is hard.
b. it is ductile.
c. it is a gas.
d. it has low reactivity.

Option (B) is the correct answer.

Explanation:

Cesium is a group 1A element and therefore, it is a metal. Alkali metals are soft, malleable and ductile.

And, group 1A elements being metals are good conductors of heat and electricity.

Group 1A elements are highly reactive in nature. Hence, cesium is also reactive in nature.  Also, cesium is not a gas.

Therefore, we can conclude that a property cesium would most likely have is that it is ductile.

beta decay is the answer