In humans, protein coding genes are mainly organized as exons and introns. There are intergenic regions that transcribe into various types of non-coding RNA (not translating into protein). some introns may harbor also transcription units, which are
always other protein coding genes
protein coding gene and RNA coding genes
always RNA coding genes
pseudo genes
Some introns may harbor transcription units, which can include both protein-coding genes and RNA coding genes. In these cases, the intron region can contain genetic information for both protein-coding transcripts and non-coding RNA transcripts.
The presence of non-coding RNA and the complexity of gene organization in humans highlight the diverse functional elements of the genome beyond protein-coding genes. These non-coding elements play important roles in gene regulation and the overall complexity of cellular processes. Hence, the correct answer is option 2.