(a) Which of the following nuclear pre-mRNA nucleotide sequences potentially contains an intron?
(1) 5′-UGACCAUGGCGCUAACACUGCCAAU UGGCAAUACUGACCUGAUAGCAUCAGCCAA-3′ 

(2) 5′-UAGUCUCAUCUGUCCAUUGACUUCGAAA CUGAAUCGUAACUCCUACGUCUAUGGA-3′
(3) 5′-UAGCUGUUUGUCAUGACUGACUGGUCA CUAUCGUACUAACCUGUCAUGCAAUGUC-3′
(4) 5′-UAGCAGUUCUGUCGCCUCGUGGUGCUG CUGGCCCUUCGUCGCUCGGGCUUAGCUA-3′
(5) 5′-UAGGUUCGCAUUGACGUACUUCUGAAAC UACUAACUACUAACGCAUCGAGUCUCAA-3′
(b) One of the five pre-mRNAs shown in (a) may undergo RNA splicing to excise an intron sequence. What mRNA nucleotide sequence would be expected to result from this splicing event?