The correct answer is: D. Bromine
Bromine is a non-metallic chemical element with the symbol Br and atomic number 35. It is the third member of the halogen group and is a highly reactive, corrosive, and flammable pale red-brown liquid at standard temperature and pressure. Bromine occurs naturally in the Earth’s crust and atmosphere in trace amounts. It is produced commercially as a byproduct of the electrolysis of brine.
Bromine is used in a variety of industrial applications, including the production of flame retardants, dyes, and pharmaceuticals. It is also used in some medical treatments, such as the treatment of hyperthyroidism.
Fluorine, chlorine, and iodine are all non-metallic elements that are gases at room temperature. Fluorine is the most reactive element in the periodic table, and it is a pale yellow gas. Chlorine is a greenish-yellow gas that is used in bleach and disinfectants. Iodine is a purple-black solid that is used in antiseptics and photography.
Therefore, the only non-metallic substance present in liquid state at room temperature is bromine.