Question: What is the correct way to run all the doctests in a given file from the command line?

1. `python3 -m doctest <_filename_>`
2. `python3 <_filename_>`
3. `python3 <_filename_> rundoctests`
4. `python3 doctest`

Answer: The correct answer of the above question is Option A:`python3 -m doctest <_filename_>`