Meaning of off-hand

Test No. [color=blue]incompl/inter-95 “Letter of Complaint (2)”, question 8

who were most hand

(a) to
(b) in
(c) by
(d) off

Test No. [color=blue]incompl/inter-95 “Letter of Complaint (2)”, answer 8

who were most off hand

Correct answer: (d) off

Your answer was: [color=red]incorrect
who were most in hand

I don’t get it? off hand here means?

Those people in technical support weren’t well prepared for their job. They couldn’t answer any questions or give advice.[YSaerTTEW443543]

TOEIC listening, photographs: Autobahn[YSaerTTEW443543]