none of which was/were?

We looked at five or six second-hand cars, none of which was/were suitable

Która opcja jest poprawna? Wydawało mi się, że was, a w odpowiedziach jest were.

cars to jest l. mnoga, ....cars are, cars were....

MGL: Neither and none take a singular or plural verb with plural nouns; a plural verb is more informal:
None of the students is/are willing to accept the increase in coursework.

Czyli w sumie oba?

w sumie oba