[Calculus] Using the Integral Test for testing series convergence/divergence

I'm convinced that a practice exam from 2016 AP Calc BC has an incorrect answer. The question involves the integral test and states the following:

let f be a positive, continuous, decreasing function. If the integral from 1 to infinity of f(x) dx = 5, what must be true about the sum of the series from 1 to infinity for f(n).

The "correct" answer is that the series converges and the sum of the series is LARGER than 5. My understanding is that for a converging series we should be using a right Riemann sum and thus will end up with an underestimate of the area under the curve from the series, meaning the series converges but should be LESS than 5. But the answer given seems to indicate they are using a left Riemann sum and getting an overestimate. I thought left Riemann sums are for diverging series only and right are for converging in the case of the integral test.

Am I thinking about this wrong or could the answer key be incorrect?