Answer:
"You must have the second one in 1 month and the third in 6 months."d
Explanation:
The standard dosage of shot duration for Hepatitis B  after the first injection dosage assuming  0 is  1 month, and after this  6 months later.This is called the 3-shorts Hepatitis B vaccine.
     Thus from  0, followed by  1 month  and later to -6(months).This is the intervals for maximum  immune response to build up resistance against the virus within limited duration
The primary objective is to get maximum protection within limited duration with a few doses of the vaccine..