They're not political answers; they're honest and accurate answers.
There's no one best style for anything and everyone. Any solid program with a decent emphasis on actual use as well as tradition or tournament, or whatever, will assist the original poster in developing some self-defense skills and self-confidence. There's a reason that police and the military don't just send people out to get black belts in XYZ art; they pull a handful of effective techniques and principles out of multiple systems, and teach them in their most basic and most direct application. That's the only way to quickly learn combatives. But... that's not really martial arts training -- it's a self-defense class.
The poster listed 4 martial arts; half of them were primarily sport-oriented (boxing and Muay Thai). One is a compromise of sport and combat (BJJ, where much depends on the teacher's emphasis -- but much of the so-called proof of it's effectiveness comes from the MMA ring), and the last (Krav Maga) is claimed to be 100% street effective/combative techniques -- but I can't help but suspect that there's going to be wide disparity in teachers, and I'm always suspicious of hype like that. Beyond that -- I just wonder how many really experienced instructors are around, since it's only been publicly promoted in the last several years.
There's no magic answer to the original poster's question of "what should I study" unless the person seeking to advise them knows that person well, and also knows the majority of the instructors that are in the area. Boxing and Muay Thai will give quick ring experience of being hit and hitting. Both can be learned to a ring-effective level in mere weeks, for a talented athlete. BJJ is more complex -- but all three of these also focus on a lot of actual application of techniques on a partner or opponent. I don't know enough about how Krav Maga is taught to speak with any authority on it.
And nothing I've mentioned so far addresses issues like class chemistry, schedule or cost. The original poster is 16; even if we assume that class cost prices (within reason) are no object -- we don't know how they plan to get to classes, what they're school schedule is like (it'd be hard to be in the 10 AM 'super-ultimate-fighter class' if you're supposed to be in school at 10 AM, wouldn't it?), or even what's actually available in their area.
