What does the phrasal verb 'make out' mean? Is it an idiom?

[Rich7]

Test No. incompl/inter-22 "Cross Questions", question 9

Jane: It's some kind of note from Joe next door - no I ..........

(a) can't make it out
(b) can't make it off
(c) can't make it in
(d) can't make it on

Test No. incompl/inter-22 "Cross Questions", answer 9

Jane: It's some kind of note from Joe next door - no I can't make it out.

Correct answer: (a) can't make it out

Your answer was: incorrect
Jane: It's some kind of note from Joe next door - no I can't make it in.
_________________________

I don't understand this expression could you please help me out?

[Torsten]

Richard,

If you can make something out, you manage to see or hear it.
If you make out something that is difficult to understand, you manage to understand it.

TOEIC short conversations: Co-workers talk about the installation of the company's new computer system.

[Borislav]

Mr.Torsten can you give more examples for make sth out and make out ?

[Watie]

Could you please explain to me summarizing the meaning of this sentence?
(a) can't make it off
(b) can't make it in
(c) can't make it on

Thank you.