Pot luck. I too fell foul of this question. Just another question on here that you have to memorise since you have no context.
Yes Duo, please accept both "d'elle" and "d'elles" as there is not context here.
d'elle or d'elles - how does one tell the difference in the audio?
Also, why don't the Report answer options for the "Type what you hear" type questions don't have an option for "my answer should be accepted."
I typed "je ne me souviens pas d'elle" and was marked wrong....
You don't, you either get it right or get it wrong. Note which one is which and next time the audio exercise comes up again (which it will) just answer the one it accepts. Every time the exercise comes up again, answer it the same way.
Hopefully you won't see the question again after you finish the skill!
the singular "elle" should be accepted. There is no diffrence in the sound between the singular and the plural.
It accepts the singular form, but tells you you have a spelling error. (Gallic shrugging of shoulders...)
They might be listening: I typed d'elle which was marked correct, but it said I had a typo!
The same problem as others have too. I typed Je ne me souviens pas d'elle, and confused; because the pronunciation of both is the same but Duo does not accept the singular form. :-(