reading is possible

writing is possible

both reading is possible & writing is possible

all the above comments are true

after write operation reading is possible without closing and re-opening

reading is possible

writing is possible

All of the above

is a function

gives the current file position indicator

can be used to find the size of a file

All of the above

needs 3 arguments

makes the rewind function unnecessary

is meant for checking whether a given file exists or not

both needs 3 arguments and makes the rewind function unnecessary

a mode

w mode

w+ mode

a+mode