26. How are complex processes such as sporulation, synthesis of flagella, and nitrogen fixation that require the transcription ofmultiple sets of genes regulated in bacteria?(A) Multiple operons are simultaneously induced.(B) Cascades of sigma factors synthesized in a temporal order, allow the turning on of successive sets of genes.(C) The end product of one operon is used as an inducer of the next operon in sequence.(D) There are single operons consisting of many genes for each of these processes.