BB has traveled to remote houses in the Caribbean to

BB has traveled to remote houses in the Caribbean to photograph the art of Indian women,( whose paintings are brillantly colored,), their geometrical symmetries elaborated with old and new iconography and a style that varies from female to female and house to house.)

A) This is the right answer, but why? Actually, you can tell because it sounds the best among the remaining choices but due to copyright I am just going to the main point.

B) whose murals are brillantly colored, their geometrical symmetries are embellished with old and new iconography, and their style is varying among women and houses.

ETS claims the inserting of are before embellished into an independent clause will create an run-on sentence. Why?