Which of the following acts as a substrate for $RNA$ polymerase enzymes?

Which of the following statements about $RNA$ polymerase are correct?
$i. \;RNA\; \text{polymerase } I \text{ transcribes } rRNAs.$
$ii. \;RNA \; \text{polymerase } II \text{ transcribes } snRNAs.$
$iii. \;RNA \; \text{polymerase } III \text{ transcribes } hnRNA.$
$iv. \;RNA \; \text{polymerase } II \text{ transcribes } hnRNAs.$

If the sequence of the coding strand in a $\text{DNA}$ molecule is $\text{5'-ATCGATCGACTG-3'}$,then the sequence of $\text{RNA}$ transcribed from the template strand would be:

Where is the transcription unit found?

Identify $a, b$ and $c$ in the given process of transcription.

Which of the following is not a region of a transcription unit?