Final answer:
The correct order of ionization energies for bromine (Br), chlorine (Cl), and selenium (Se) is Cl > Br > Se, following the periodic trend of increasing ionization energy from left to right across a period and decreasing down a group.
Step-by-step explanation:
The order of ionization energies for the elements bromine (Br), chlorine (Cl), and selenium (Se) can be determined by considering their positions on the periodic table and the general trends of ionization energy. Ionization energy typically increases across a period (from left to right) and decreases down a group (from top to bottom). Chlorine, being above bromine in the same group, will have a higher ionization energy. Selenium, being in the same period as bromine but to the left, should have a lower ionization energy than bromine. Therefore, the correct order is Cl > Br > Se, which corresponds to option d).