What ALWAYS occurs simultaneously with reduction?

Oxidation-reduction process or redox reaction are the reactions where oxidation and reduction processes happens simultaneously.

the only liquid elements at standard temperature and pressure are bromine (br) and mercury (hg). although, elements caesium (cs), rubidium (rb), francium (fr) and gallium (ga) become liquid at or just above room temperature.

explanation:

i'm assuming that the correct answer is indeed the first one/ "a"..