Answer: Option (B) is the correct answer.
Step-by-step explanation:
Non-metals are electron deficient in nature and in order to completely fill their octet they tend to readily react with an electron donor atom.
Here, iodine, chlorine and boron are all non-metals. Whereas germanium is a metalloid.
As it is known that when we move from left to right in a periodic table there will be increase in reactivity due to increase in electronegativity. On the other hand, when we move down a group reactivity of non-metals decreases.
Thus, we can conclude that out of the given options chlorine (Cl) is a non-metal which is most reactive.