Are rhyme and reason something like an idion or phrase?

[Zarinamo]

English Language Tests, Intermediate level

ESL/EFL Test #145 "Short Idioms Exam", question 3

Joanne left abruptly -- without rhyme or ..........

(a) verse
(b) reason
(c) cause
(d) record

English Language Tests, Intermediate level

ESL/EFL Test #145 "Short Idioms Exam", answer 3

Joanne left abruptly -- without rhyme or reason.

Correct answer: (b) reason

Your answer was: incorrect
Joanne left abruptly -- without rhyme or verse.
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HI,
Are rhyme and reason something like an idion or phrase???
Thank you.

[Mister Micawber]

.
Yes. "Without rhyme or reason" means unexplainably.
.
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Native English teacher at Mister Micawber's