'I couldn't agree with you more' = 'I agree with you completely'

[Phoboe]

English Language Tests, Intermediate level

ESL/EFL Test #60 "Cliches", question 2

........., I couldn't agree with you more.

(a) Totally
(b) Clearly
(c) Finally
(d) Absolutely

English Language Tests, Intermediate level

ESL/EFL Test #60 "Cliches", answer 2

Absolutely, I couldn't agree with you more.

Correct answer: (d) Absolutely
_________________________

Please explain what this mean?

Phoboe

[Mister Micawber]

.
'I couldn't agree with you more' = I agree with you completely (It is impossible for me to agree more, because I already agree 100%).
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber