(d) : $mRNA$ is not made directly in a eukaryotic cell. It is transcribed as heterogeneous nuclear $RNA\ (hnRNA)$ in the nucleus. $hnRNA$ contains introns and exons. The introns are removed by $RNA$ splicing leaving behind the exons,which contain the information. The exonic regions of $RNA$ are joined together to produce a single chain $RNA$ required for functioning as translational template.