off the coach vs. out of the coach

[uha]

English Error, Elementary Level

ESL/EFL Test #19 "Guided tour", question 10

That means you must now all get of the coach and we will spend the next hour and a half walking to our destination.

(a) means
(b) of
(c) spend

English Error, Elementary Level

ESL/EFL Test #19 "Guided tour", answer 10

That means you must now all get off the coach and we will spend the next hour and a half walking to our destination.

Correct entry: off
The error was: (b) of

You have found the error but your entry is incorrect.
That means you must now all get out of the coach and we will spend the next hour and a half walking to our destination.
_________________________

Why my entry OUT OF is incorrect?

uha

[Mister Micawber]

.
It is not incorrect. I guess the software accepts only single-word answers.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber