Answer: Option (c) is the correct answer.
Step-by-step explanation:
An activity series is defined as the series that shows metals arranged in decreasing order according to their reactivity.
Atomic mass is the sum of total number of protons and neutrons present in an atom.
Atomic radius is defined as the distance from the center of the nucleus to the outer most shell. Larger is the size of an atom, greater will be its atomic radius.
Reactivity is the ability of an atom to readily combine or react with a substance in order to gain stability.
Solubility is water means whether a compound or molecule dissociate into ions or not if dissolved in water.
Therefore, we can conclude that reactivity is the property of an element determines its position in the activity series.