Having often been thought of as still a city of working-class neighbor

IF you read the sentence you will see that sentence intends to show CONTRAST that THOUGHT OF AS OCCUPIED BY WORKING CLASS....CHICAGO IS OCCUPIED BY POOR PEOPLE.
SO to show the contrast we need contrasting words such as: ALTHOUGH/EVEN THOUGH/BUT ..etc

(A) Having often been thought of as still a city of working-class neightborhoods, Chicago is increasingly populated by poor people.
WRONG.
-no contrasting word present.
-incorrect placement of STILL

(B) It is still often thought of as a city of working-class neighborhoods, and Chicago is increasingly populated by poor people.
WRONG.
-NO CONTRASTING WORD
-USE OF AND..makes it two IC hence the intended meaning is lost.

(C) In sprite of still often being though of as a city of working-class neighborhoods, the people who polulate Chicago are increasingly poor.
WRONG.
-BEING makes it unnecessary wordy.
-In sprite of still often being though of as a city of working-class neighborhoods==>this whole thing is modifying THE PEOPLE ..which is wrong it should modify CHICAGO.

(D) It is still often though of as a city of working-class neighborhoods, but the people who populate Chicago are increasingly poor.
WRONG.
-NON PARALLEL STRUCTURE ...First clause subject : IT(CHICAGO)....Second clause subject: the people....seems we are comparing CHICAGO with PEOPLE.
HENCE intended meaning is not very clear.

(E) Although still often though of as a city of working-class neighborhoods, Chicago is increasingly populated by poor people.
CORRECT.

HOPE IT HELPS