During translation initiation in prokaryotes, a GTP molecule is needed in : -

Initiation of translation in prokaryotes takes place in steps, with the help of initiation factors IF1, IF2 and IF3.
First the 30S subunit (with IF3) binds to the mRNA at the Shine–Dalgarno sequence. This step does not need GTP.
Next, the initiator tRNA (fMet-tRNA$^{fMet}$) is brought to the start codon AUG on the 30S–mRNA complex by IF2, which is bound to GTP (IF2–GTP–fMet-tRNA). So GTP is needed for the association of fMet-tRNA with the 30S–mRNA complex, forming the 30S initiation complex.
Finally the 50S subunit joins; the GTP bound to IF2 is hydrolysed to GDP + $P_i$ at this time, and the initiation factors are released.
Formation of formyl-met-tRNA (charging and formylation) uses ATP, not GTP.
So, as per the answer key, GTP is needed in the association of the 30S–mRNA complex with formyl-met-tRNA.