Answer 1

There is no "Best" in languages. each language is used in it's own special way.
C and C++ are used for running fast useful programs(as in missile's or games)
Python is useful for machine learning and so on...
HTML/CSS/JS is useful for front end developing.
SQL is used for databases.
It all depends on what you want to work about.

Although the highest payed languages are probably JS/Python since it's more relevant today.