The correct option is A Prepatent period
The time between sporozoite inoculation and the appearance of the parasites in the blood is defined as the pre-patent period. During this period, the Plasmodium do not appear in the blood.
Incubation periods tend to be a little longer and are defined as the time between sporozoite inoculation and the onset of the symptoms.
Thus, the correct answer is option (B), 'Prepatent period'.