Task: Question Answering
Input (English): Question: The chemical reactions of the splicing process of the introns during the maturation of the pre-mRNAs consists of: 
 Options:  <1> An oxidation-reduction reaction. <2> A transesterification reaction. <3> Two sequential transesterification reactions. <4> Three sequential transesterification reactions. <5> A transesterification reaction followed by another oxidation reaction.
Output (English): 3