B. Temporary hope this helped :)
Answer is: dispersion forces.
The London dispersion force is the weakest intermolecular force.
Dispersion force is also called an induced dipole-induced dipole attraction.
The London dispersion force (intermolecular force) is a temporary attractive force between molecules.
The dipole beetween iodine and bromine is weak.
Simple,
take a look at your periodic table, if you have it labeled look at the Halogen
Group, it includes: Flourine, Chlorine, Bromine, Iodine, and Astatine.
Now, a period on the periodic table is read from left to right, and goes
down the rows of the periodic table.
Go to Period 5, go all the way to the Halogens, what is there?
Iodine.
Thus, your answer.