Immediate allergy reaction (type I allergic reaction) is:
a) An allergic or immune response that begins within a period lasting from a few minutes to about an hour after exposure to an antigen to which the individual has been sensitized
b) An allergic reaction that becomes apparent only hours after contact
c) An allergic reaction that results from the formation of antigen-antibody complexes between a foreign antigen and IgM or IgG immunoglobulins. (It occurs during blood transfusion reactions and in hemolytic disease of the newborn)
d) An allergic reaction that is due to the presence of elevated levels of antigen-antibody complexes that cause tissue damage
