The diagram shown here is part of an RNA transcript containing four open reading frames (M, H, K, and L) and three introns (1, 2, 3). The sites labeled d1-d3 are nucleotides immediately before each intron on the 5' side and those labeled a1-a3 are nucleotides immediately after each intron on the 3' side. Splicing out an intron involves a spliceosome facilitating the cleavage of the DNA at the d and a sites at either end of the intron. A missense mutation takes place in open reading frame H. In which possible alternative splice forms of the transcript would the missense mutation not affect the polypeptide product?
A)d1-a1 + d2-a2 + d3-a3 B)d1-a2 + d3-a3 C)d1-a1 + d2-a3 D)d1-a3 E)None of the answer options is correct.