our analysts have spelled out what happened

[English Learner]

English Language Tests, Intermediate level

ESL/EFL Test #880 "In a Meeting: Phrasal Verbs", question 7

Chairman: If you look at the sales' graphs, you can see that our analysts have spelled ......... what happened last month.

(a) aside
(b) out
(c) through
(d) up

English Language Tests, Intermediate level

ESL/EFL Test #880 "In a Meeting: Phrasal Verbs", answer 7

Chairman: If you look at the sales' graphs, you can see that our analysts have spelled out what happened last month.

Correct answer: (b) out

Your answer was: incorrect
Chairman: If you look at the sales' graphs, you can see that our analysts have spelled up what happened last month.
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i don't understand exactly the meaning of spell out in this situation. Could you give me the explanation by example

[Beeesneees]

The phrasal verb to spell comething out means to explain something in a simple, clear way:

You know what I mean—I'm sure I don't need to spell it out for you.
Let me spell out why we need more money for this project.
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Cheers m' dears!