Comments should give the reader the background of the programmer.
be written for every line of code.
communicate the purpose of the code that follows it.
give information about how many hours it took to write the code.

Correct answer is:

communicate the purpose of the code that follows it.

Explanation:

Let have a look at each option

comment should give the reader the background of the programmer.

Comments are unable to do so.

Be written on every line

No, it is not need as comment are useful only to explain difficult or complex part of code.

communicate the purpose of the code that follows it.

yes, this option is true, as comments will give hints to programmer about the piece of code.

give information about how many hours it took to write the code

No, comments can answer it,

the formula for work is

f*d

therefore work=2.0n*3.0=6n*m