sherxon
I think GMAC would not use "and are also"
I think you're right.
More generally, this problem is a mess. There are at least 3 significant issues:
• The correctly parallel structures are needlessly wordy (as sherxon points out above).
• The underline is too long.
GMAC's underlines always go precisely from the FIRST DIFFERENCE to the LAST DIFFERENCE. You will never,
ever, EVER see the same words at the beginning or end of all 5 underlines.
Thus, the words "dentistry to cosmetic dentistry" should NOT be underlined. The underlined part needs to start at
is/is/is/is/occurs.
• Choice A isn't wrong enough.
The only issue in A is the "due to" modifier, which mistakenly attributes the shift to
the "adults" (= dental patients) THEMSELVES rather than to the given trends in their dental hygiene and personal priorities.
When GMAC has misused this type of modifier in official problems, that error has always co-occurred with other issues; I've never seen an official wrong answer that's only wrong for this reason (and I'm quite confident I won't see one going forward, since this type of issue—which rests on a lesser-known modifier rule that has to be memorized—is exactly the kind of thing that GMAC has purged from the test in recent years to ensure fairness for non-native English learners).
Treat other problems from this source with great caution. Getting accustomed to problem-writing conventions that are wildly different from GMAC's is definitely something you want to avoid.