User blog comment:Ygrain/The ending: there MUST be something more to it/@comment-2228120-20120619162952/@comment-4950455-20120622234731

I'm not sure how much of a choice it has. The Catalyst isn't really offering you options so much as explaining (or not explaining, really) them to you - you can Destroy the Reapers regardless of what it says. In fact, regardless of whether it's lying about all synthetics being destroyed, it's clearly trying to talk you out of choosing Destroy.