Witch of the following is not one of the stages of star evolution?

a: white dwarf
b: supergiant
c: blue giant
d: red giant

For me it seems quite obvious, according to the list of represented options there is one which does not matches, not only because it is wrong, but actually because one of them is a stellar core remnant and it is A: White dwarf. 
I'm sure it helps 

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen