Step 1: The guiding rule is that live viral or live bacterial vaccines are contraindicated in pregnancy because of the theoretical risk of fetal infection from the attenuated organism.
Step 2: The chicken pox (varicella) vaccine is a live attenuated vaccine, so it is contraindicated in pregnancy. Other live vaccines to avoid include measles, mumps, rubella, BCG, oral polio, and yellow fever.
Step 3: Rabies vaccine and hepatitis B vaccine are inactivated, and tetanus toxoid is a toxoid - all three are safe and in fact tetanus toxoid is routinely given in pregnancy. Therefore the contraindicated vaccine among the options is chicken pox.