HELP ME PLZZZ To what is the speaker most closely referring with the phrase withering injustice in the passage below (paragraph 2)?

Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of their captivity.
Answer choices for the above question

A. the experience of enslaved Africans before the Emancipation Proclamation

B. the weather on the day of the march

C. the cruelty African Americans continue to experience in the present

D. the personalities of the politicians who were in power during the speaker’s time