How is a block of code $($the body of a loop, a function, etc.$)$ defined in Python?

Choose one of the following answers.

Using a pair of double quotation marks, e$.$g$.$ "codeblock"

Using a pair of curly brackets, e$.$g$.\{$codeblock$\}$

By indenting the block

Using begin, end keywords, e$.$g$.$ begin codeblock end