Explain Why Yeast Genes with a Single Intron Have Essentially

Explain why yeast genes with a single intron have essentially no alternative splicing.

A) Yeast genes never have alternative splicing.
B) Removal of a single intron leads to splicing of the poly-A tail which prevents further splicing.
C) Methylation of the single intron prevents further splicing.
D) Removal of a single intron only leads to one possible outcome for spliced mRNA.
E) None of the above.