Alternative splicing allows for different proteins to be encoded
by the same DNA sequence. The crista gene has 6 exons. If exon 3 is
not included in the mature mRNA of an alternatively spliced mRNA,
exon 3 must have been excised by splicing. During the action of
just one assembled spliceosome, with what other RNA sequences would
exon 3 have been removed?

a. Introns 1 and 4

b. Introns 2 and 3

c. intron 3

d. AAUAAA sequence

e. TATA box

f. rut site

g. exon 2 and 3