Answer 1

There is no 'best', every language are important. It is depends on you where you want to go or what you want to develop or what you want to be.

for example :- if you want to develop website then you have to know html, css, javascript, ajax, json, bootstrap, java, c#, php, SQL, ruby on rails

if you want to develop game then learn java, c# unity unreal engine.

if you want to be data scientist then you have to know python, data science, R language.

if you want to with robotics then learn embedded, C++