Bromine (Br) is the only element listed that is a diatomic element. I believe that Bromine is going to be your answer.
B) Mg is the alkaline earth metal w/12 protons so following the periodic table to the halogen in the same period is
Cl: Chlorine
C) The Neutral noble has w/ 18 electrons is argon so the metal in the same row is
Na: Sodium
Answer: Fluorine and chlorine are gases. Bromine is one of only two liquid elements, and iodine is a solid.
There are 2 sig figs in 0.092