Which among the following is the mode of reproduction in unicellular organisms?

Unicellular organisms generally divide by the means of asexual reproduction. Asexual reproduction is a mode of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only. There are various asexual reproduction methods by which the unicellular organisms divide.

• Budding is a type of asexual reproduction by which offsprings arise from a single organism.

• Fragmentation is the form of asexual reproduction in which an organism is split into mature, fully grown individuals that are clones of the original organism.

• Multiple fission is that type of asexual reproduction in which the parental body divides into many daughter cells simultaneously during the unfavourable conditions.
• So, the correct answer is option D.