How can you increase your awareness of hereditary diseases?
a. performing self-checks
b. getting screened by a professional
c. looking for indicators
d. all of the above

I would say all of the above. Performing self checks may actually be good but if you are the only one who is performing this self check, you still have to confirm by going to a professional. Looking for indicators is also okay but even if you observe indicators for hereditary diseases, you still have to confirm your suspicions by getting screened by a professional. So in any case, everything will lead to getting screened by a professional. Self checks and looking for indicators will give you suspicions only and the professional screening will be the one to confirm. 

A. vitamin c is your answer