Which of the following is absolutely necessary for seed germination?

Which of the following is not a man-made method to overcome seed dormancy?
$(I)$ Seed coat broken by using knives,sandpapers,etc.
$(II)$ Passage of seed through the digestive tract of animals.
$(III)$ Effect of inhibitory substances can be removed by subjecting the seeds to chilling conditions.
$(IV)$ By application of certain chemicals like gibberellic acid and nitrates.

Which hormone is responsible for breaking seed dormancy?

Why do newly harvested potato tubers not germinate even when placed in favourable conditions?

What is phenolic acid?

Positively photoblastic seeds germinate only in the presence of