Difference between dialect and accent

[Rich7]

Test No. incompl/inter-93 "Hotchpotch", question 8

He spoke the language in a regional ........., which made it impossible for me to understand him.

(a) voice
(b) accent
(c) jargon
(d) dialect

Test No. incompl/inter-93 "Hotchpotch", answer 8

He spoke the language in a regional dialect, which made it impossible for me to understand him.

Correct answer: (d) dialect

Your answer was: incorrect
He spoke the language in a regional accent, which made it impossible for me to understand him.
_________________________

what would be the difference here If I used accent?

[Torsten]

A dialect is usually spoken by people who live in a certain region of a country. Those people speak their mother tongue in their own individual way. For example, many Scottish people have a dialect.
An accent usually describes the way people pronounce words of a language that is different from their mother tongue. For example, Arnold Schwarzenegger speaks English with an Austrian accent.

TOEFL listening discussions: Why is the student talking to the advisor?

[Rich7]

You're right