by jlucero Fri Aug 02, 2013 1:40 pm
Per forum rules, we can't post questions from paid resources, including the OG. If you have a specific question about something mentioned in an OG question, you can ask that.
As for your question- if the OG explanation says it, then it must be true. This is an issue of parallelism and as long as there are actual elements that SHOULD be parallel, keeping them in parallel voice is preferred.
Joe Lucero
Manhattan GMAT Instructor