For striking:
boxing/ muay thai
For grappling & takedowns:
wrestling/ bjj/ sambo
If MMA classes are available, then take them too.
There are weaknesses in each martial art. It’s not enough to know only one.
The most dangerous fighter is a well rounded fighter.
For the street, most people can’t fight. Boxing is more than enough for them.
But you never know if the fight is going to ground. It makes sense to at least know one grappling martial art. Furthermore, street fighting is dangerous and people die. Avoid it unless there is no other way.