What does the expression 'no idea' mean?

[Jorik]

English Grammar Tests, Elementary Level

ESL/EFL Test #31 "Responses (4)", question 9

Mike: 'So what do you think is the answer?'
Jane: '.........'

(a) No idea.
(b) Not idea.
(c) Negative idea.
(d) Small idea.

English Grammar Tests, Elementary Level

ESL/EFL Test #31 "Responses (4)", answer 9

Mike: 'So what do you think is the answer?'
Jane: 'No idea.'

Correct answer: (a) No idea.
_________________________

No idea?

Jorik

[Mister Micawber]

.
'No idea' = '[I have] no idea' = I do not know at all.
.
_________________
Native English teacher at Mister Micawber's