If an organism had a mutation in a gene that codes for ribosomal protein, which of the following would be affected ?
a) dna replication
b) transcription
c) translation
d) gene expression

The answer is C. translation.
Translation is a process of a protein synthesis based on the ribonucleotide sequence of messenger RNA (mRNA). During translation, mRNA attaches to a complex molecular machinery ribosomes. Ribosomes consist of two subunits - a small and a large one. The small subunit reads mRNA sequence, while the large one joins amino acids brought by transport tRNA. The sequence of a newly synthesised protein depends on the sequence of mRNA and complementarity between mRNA and tRNA. Therefore, if a mutation in a gene that codes for ribosomal protein occurs, the new protein will not be synthesised, i.e. the translation will be affected.