Given the task definition and input, reply with output. In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: To detect small deletions or duplications at the genomic level, the technique of choice would be:
Options: <1> Karyotype of bands G. <2> Genomic microarrays. <3> Expression microarrays. <4> PCR <5> RT-PCR.
2