File Handling - General Questions

What is the output of the following code?

import io
f = io.StringIO('a\nb\nc\n')
print(len(f.readlines()))

Which method writes a list of strings to a file without adding newlines?

Which mode opens a file for writing and creates it (erasing old contents if it exists)?

Which module serialises Python objects to bytes and back?

What is the output of the following code?

import io
f = io.StringIO('abc')
print(f.read(2), f.read())