I think it’s either B or D I’m so sorry if it’s wrong
"B. I understand that Dr. Elliott earned <span>his M.D. at Columbia University" has correct punctuation since these are all proper titles, although it's not uncommon to see "MD" without periods. </span>
If you are looking for a title for like an essay on this topic you can write something like......"The injustice of Sexism" or "Sexism in today's world".
I know that it means to be happy