The correct option is B Tobacco
The phenomenon of photoperiodism was first explained in tobacco plant. This phenomenon is a recent discovery. Scientists first linked the onset of flowering with day length in the 1920s, during experiments with soybeans and tobacco. Most tobacco plants flower during the summer. However, around 1920, a mutant appeared in a field of tobacco growing near Washington, D.C. The plant had unusually large leaves and grew to an enormous height without ever flowering. This new variety was named as 'Maryland Mammoth'.