This abbreviation could stand for sound effects and so it could be needed in scripts for television ads (D).
In the copy for billboards (A) sound effects are irrelevant just like in the copy for magazine ads (B) or newspaper ads (C), because sound effects are not needed in these kinds of advertisement. So, as sound effects can only be used in one of these choices, television ads, the abbreviation SFX will be needed in scripts for TV ads. Also, similar abbreviations could only be used in the script of an advert and not in the copy that is the final text that will be shown to the public, so choices A, B, and C are wrong for this reason as well.
