Choose the correct answer from the list below. Not all of the answers will be used. -______________: These small nuclear RNAs form the catalytic center of the spliceosome.
A)poly(A) tail B)methylation C)alternative splicing D)spliceosome E)U2 and U6 F)U4, U5, and U6 G)spliced H)translation I)RNA editing J)GU K)ribozyme L)RNA polymerase I M)ATP