Answer: c. are spliced out of the message.
Explanation: Intron are non-coding portion of the DNA sequence. They do not code for any specific amino acid and are spliced or removed before splicing.
Exons are DNA sequence that code for specific amino acid they are usually left after introns are removed and are joined together before translation into amino acid sequence. Intron splicing can lead to splicing some exons which can lead to formation of an entirely new amino acid or protein.
Spliceosome are enzymes for splicing introns.