"They introduced me to their parents."
Translation:Przedstawiły mnie ich rodzicom.
- "swoim" - the subject's parents
- "ich" - either subject's or someone else's parents
So both options should be marked as correct here as we don't know the context.
Yes, certainly both are correct, but the interpretation of "ich rodzicom" (which is the default here) would be highly unusual in English without some contextual clues to support it.
Duo said i have a typo... But where is it? >>> "Oni przedstawiły mnie ich rodzicom."
The typo is either 'Oni' or 'przedstawiły', because they don't match. 'Oni' is masculine plural, while 'przedstawiły' is non-masculine plural.
You can write: 'Oni przedstawili' (if the subject is a group with at least one male) OR 'One przedstawiły' (if the subject is a group with no males).