I think the issue is with tenses and awkwardness of construction.

First tackling the confusion with they/them/their .........all refer to the parents.

Now lets look at the choices:

A - looks good keep as a contender
B - If we make do with the simple past it is preferable to the perfect tenses, hence A is better than B hence do not keep.
C - Awkward construction - as if during??
D - when we use 'did' we are thinking in terms of ellipsis here, let us fill out the ellipsis after 'did' - 'did ..appear' this construction does not make grammatical sense
E - changes meaning. 'appear to them as though in adolescence' they are adolescents to begin with.

Hence pick A