Please Read the Clinical Scenario, and Then Answer the Question

Please read the clinical scenario, and then answer the question that follow to become familiar with the traditional NCLEX question format.
Joseph is a 6-year-old male presenting to your pediatric office with chickenpox. He has had his infection for about 1 week, and his mom is concerned about Joseph’s 8-year-old sister, Judith, because she had a long, painful infection of chickenpox 2 years before. Of note, Joseph was not vaccinated against chickenpox when he was younger, because his mom did not think it was that serious of a virus, and she wanted to spare him the extra injection.
-Which of the following explanations tells you why Joseph became infected with chickenpox in the first place?

A) Joseph should not have been infected because he had passive natural immunity from breastfeeding as a baby.
B) His mother should have had gamma globulin administered so he would have passive artificial immunity.
C) There is no way Joseph could have been protected from the infection,since he did not receive active artificial immunity through the form of a vaccine.
D) Joseph probably has a primary immunodeficiency disease,otherwise there is no reason humans should be infected with chickenpox.