Meaning of "wrappin one's head around of something"

[Ferma]

English Grammar Tests, Elementary Level

ESL/EFL Test #132 "Conversations and Comprehension (3)", question 7

Woman: I'm having a really hard time right now. I liked the old system a lot and I can't seem to wrap my head around the new system at all.
Man: Let's sit down and talk about it after lunch.
Woman: Thanks. I really appreciate your patience.
Man: No problem.
Narrator: What does the woman mean? .........

(a) She doesn't understand how the new system works.
(b) She has a headache.
(c) The new system is easier to manage than the old system.

English Grammar Tests, Elementary Level

ESL/EFL Test #132 "Conversations and Comprehension (3)", answer 7

Woman: I'm having a really hard time right now. I liked the old system a lot and I can't seem to wrap my head around the new system at all.
Man: Let's sit down and talk about it after lunch.
Woman: Thanks. I really appreciate your patience.
Man: No problem.
Narrator: What does the woman mean? She doesn't understand how the new system works.

Correct answer: (a) She doesn't understand how the new system works.
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I am sure that wrappin one's head around of something mean that the person does not understand how to use that particular thing. Is it true? Please kindly give the explanation???

Ferma

[Mister Micawber]

Wrap one's head around = understand
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Native English teacher at Mister Micawber's