GMAT Critical Reasoning (CR) | Re: These days, drug companies and health professionals alike

a) If a person has low blood cholesterol, then that person's risk of fatal heart disease is low.It cannot be assumed that the reverse condition will be true.
b) Smoking in moderation can entail as great a risk of fatal heart disease as does heavysmoking.the text doesn't talk about type of smoking
c)a high-cholesterol diet is the principal cause of death in NorthAmerica."Principal cause" is too generelized
d) The only way that smoking increases one's risk of fatal heart disease is