🗽What happens to the core of a star after a planetary nebula occurs? 🚘

Question

What happens to the core of a star after a planetary nebula occurs? 

 Answers:  

a. It contracts from a protostar to a main-sequence star. 

b. It breaks apart in a violent explosion. 

c. It becomes a white dwarf. (Correct Answer)

d. It becomes a neutron star. 

e. none of the above