Use the Following Model of a Eukaryotic Transcript to Answer

Use the following model of a eukaryotic transcript to answer the question. E1-4 refer to the exons and I1-3 refer to the introns in the pre-mRNA transcript.
5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3'
Where on a pre-mRNA transcript does a spliceosome bind?

A) to the exons
B) to the 5' UTR
C) to the 3' UTR
D) to each end of an intron