What is the Style of the dance Choreographed by Nacho Pop with result of safe?
CREATE TABLE "week_1_17_february_2008" (
  "couple" text,
  "style" text,
  "music" text,
  "choreographer" text,
  "results" text
);
SELECT "style" FROM "week_1_17_february_2008" WHERE "results"='safe' AND "choreographer"='nacho pop';