Correct Option: B

Wilhelm Johannsen was a Danish botanist, plant physiologist and geneticist. His most well-known research concerned so-called pure lines of the selffertile common bean. He was able to show that even in populations homozygous for all traits, i.e. without genetic variation, seed size followed a normal distribution. This was attributable to resource provision to the mother plant and to the position of seeds in pods and of pods on the plant. This led him to coin the terms phenotype and genotype and first used in his paper Om arvelighed i samfund og i rene linier and in his book Arvelighedslærens Elementer.] This book was rewritten, enlarged and translated to German as Elemente der exakten Erblichkeitslehre.It was in this book Johannsen introduced the term gene. This term was coined in opposition to the then common pangene that stemmed from Darwin’s theory of pangenesis.