The correct option is C Pisum sativum
Drosophila has only four pairs of chromosomes - three autosomes and one sex chromosome. Haplopappus gracilis has 2 pairs of chromosomes. It has lowest chromosome number. Pisum sativum has chromosome number 2n = 14. Ascaris is a nematode worm that has a diploid number of chromosomes equal to 4. Thus, option D is correct and other options are wrong.