meaning of "By myself"

[Goran]

Test No. errors/elem-1 "Much information", question 5

Tonight I'm going to stay at home with myself.

(a) Tonight
(b) going
(c) with

Test No. errors/elem-1 "Much information", answer 5

Tonight I'm going to stay at home by myself.

Correct entry: by
The error was: (c) with
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I think all options are right. There 's no answer.

Goran

[Alan]

You need by myself here because it is an expression meaning alone.
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English as a Second Language
You can read my ESL story Present Simple

[The French]