Even if you didn't know anything about the gene mentioned they tell you the PROTEIN serves as a precursor for making the hormones thus it has already undergone translation and the only choice that makes sense is Post-translational modification. Additionally, mRNA means it has already undergone splicing and post-transcriptional modification as it would be called hnRNA otherwise. (FA2020 pg 41)
MOPC si a oephrnorom eetpdpi .icnha
tI is sdlattnrae dna laret eeynzsm ctu sthi etiepdp in the epedpsb.itsu
rTatncpsnorii is worgn i( ahd ihts ot.)o.. b/c sti not teh RmAN htat akmse ftferdnie deeitpp rheoosnm. rrMvoeo,e tawh I ese wno si, atth poalistotcprnsairnt ofimcndaioti si rmoe or less li..gi.npcs os ora-lsttnpt.as tdfnoai.ciimo xnte eitm ew make it rorecct -);
wyosrdeK mfor .rD ocTru fomr a:lapKn
Wyh si trivalteane scnipilg ro iratpco-nrpolasinstt oimiaiftodnc ?icrtrcone
POMC is a prohormone peptide chain that gets cleaved into gamma-MSH, ACTH, gamma-lipotropin, and beta-endorphin. There's a nice figure of this in Costanzo (Fig 9-10).
It may help to remember that pathologies with increased ACTH (ie Addison's disease) can present with hyperpigmentation since MSH (melanocyte stimulating hormone) is produced alongside ACTH.
It's saying a particular protein is made from this mrna, this protein is used as a precursor to produce those two hormones. so proteins once made, they need post translational trimming of N and C propeptides to be active. like trypsinogen becomes trypsin else they are just inactive protein. So any protein to work they need to go through post translational modifications.
So if a long polypeptide string is generated from signle mRNA then cleaved → post-translational modification.
If modification happens at level of RNA which is cleaved into smaller mRNA that then give proteins → alternative splicing / post-tranSCRIPTIONAL modification.