The answer is Mutualism because they are both benefiting
I don’t know why they make everyone type more than 20 characters but B sounds like the most reasonable answer.
<span>The answer is cysteine. This is a half essential proteinogenic amino acid with the formulation of HO₂CCHCH₂SH. It is prearranged by the codons UGU and UGC. The thiol side chain in cysteine frequently partakes in enzymatic responses, as a nucleophile.</span>