Study showhat young people with higher-than-average blood pressure and their families have a history of high blood pressure are ore likely than others to develop a severe form of the condition.
a. and their families have a history of high blood pressure
b. whose families have a history of high blood pressure
c. and a history of high blood pressure runs in the family
d. whose families have a histories of high blood pressure running in them
e. with a history of high blood pressure running in their family.