The dolphins comprise the extant families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the new world river dolphins), and Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin).
The answer should be C. Once the host cell transcribes a viral gene, the RNA is formed. The RNA is then translated in order to give us the viral proteins essential for the replication of the virus So the answer is when a cell transcribes a viral gene, the host cell then translates it.
If a letter is either inserted or deleted this is called a frame shift mutation and this totally destroyes the message. A sudden change in the sequence of DNA could also silence the gene turning off transcription so that no mRNA would even be made. Or, it could enhance transcription increasing the ammount of mRNA.