Which of the Following Statements A), B) or C) Is

Which of the following statements a) , b) or c) is false?

A) By default, Hadoop expects the mapper's output and the reducer's input and output to be in the form of key-value pairs separated by a tab.
B) In a mapper script, the notation #!/usr/bin/env python3 tells Hadoop to execute the Python code using python3. This line must come before all other comments and code in the file.
C) At the time of this writing, Microsoft HDInsight clusters contain Python 2.7.12 and Python 3.5.2, so you can use f-strings in your code.
D) All of the above statements are true.