The correct option is B H. J. Muller
Herman Joseph Muller was an American geneticist, educator and Nobel laureate best known for his work on the physiological and genetic effects of radiation (X-ray mutagenesis). He was the first person who invented mutagenic effect of X-rays using Drosophila mutants. The mutagens brings a sudden heritable change in the genome. Thus, the correct answer is option B.