Let's say df is a DataFrame. How would you explain the following line of code?

df$[\text{'}$ColumnName$\text{'}]=$ range$(0,5)$

If the column ColumnName does not exist, add a new column and populate it with values $0,1,2,3,4.$

If the column ColumnName does exist, update the column values to be $0,1,2,3,4.$

Both options above.

Take a slice of column values with indexes $0,1,2,3,4.$

None of the above.