During RNA processing, a protective cap is added to the 5' end of the pre-mRNA, a tail of many adenine nucleotides is added to the 3' end, and only introns are removed. The correct option is C.
The pre-mRNA synthesized during transcription undergoes some processing before being ready for translation. The first thing is the addition of a protective cap to the 5' end and the modification of the 3' end by the addition of a long string of adenine nucleotides.
Thereafter, the pre-mRNA is spliced to remove non-coding sequences, also known as introns. The coding sequences (exons) are joined afterwards before the mRNA is ready to be translated.
More on pre-mRNA processing can be found here: https://brainly.com/question/14291596
