Which of the following is not a major modification that the primary transcript in eukaryotes undergoes before use during translation?

A) Methyl guanosine caps are added to the 5¢ ends of the primary transcripts
B) Poly(A) tails are added to the 3¢ ends of the transcripts
C) Intron sequences are spliced out of transcripts.
D) Exon sequences are spliced out of transcripts.
E) All of these are major modifications