Explanation:
Tetrad analysis confirmed the occurrence of crossing over during tetrad stage. This was first reported in neurospora.Neurospora is a genus of Ascomycete fungi. The genus name, meaning "nerve spore" refers to the characteristic striations on the spores that resemble axons. Neurospora. Neurospora crassa. Scientific classification.Neurospora is actively used in research around the world. It is important in the elucidation of molecular events involved in circadian rhythms, epigenetics and gene silencing, cell polarity, cell fusion, development, as well as many aspects of cell biology and biochemistry.Hence, the correct option is (A).