When plants are designed to contain more sets of chromosomes than normal, which of the following have humans taken advantage of ?

There are no statements given in the question to be chosen from.  plants having more than normal sets of chromosomes or multiple sets of chromosomes are said to be polyploid. one of the possible advantages could be gene redundancy. an advantage conferred by gene redundancy is that multiple copies of wild-type alleles mask the effects of recessive alleles. 

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.