This one, as with number 5, is also about style and preserving the meaning of the original sentence with the most exactness, but this involves more thinking about the "cause and effect" relationship involving time. In the original, one event happens (the band playing) and then another (the real party starting) None of the other choices, "and . . .," "although . . .," "the band beginning . . ." preserve that time feature in the original. Again, the skill involves dependent clauses and their relationships with independent ones. See the skill practice links to number 5 to review these skills.