An IFR approach to DH/MDA is NOT authorized if

• A. If RVR A is unavailable and RVR B is 1000ft
• B. If RVR is fluctuating above and below minima, regardless of ground visibility
• C. If RVR is unavailable or not reported
• D. If ground visibility is 1/4 SM

Answer: (A)

The key idea is that an IFR approach to DH or MDA must have the required visibility available and meeting the published minimums, using RVR or prevailing visibility. If a required RVR report is not available and the other reported RVR is below the minimum, you cannot authorize the approach to continue to the decision point.

Here, one runway RVR value is unavailable and the other is only 1000 ft. That means there’s no valid visibility value at or above the published minimums to support a landing decision, so the approach to DH/MDA isn’t authorized.

Brief context on the other options: fluctuations in RVR around the minimum don’t automatically bar the approach if the reported visibility at the time of the decision height meets the minima; an unavailable RVR can be acceptable if the ground visibility meets the minima, depending on the chart; and a very low ground visibility (like 1/4 SM) is typically below the required minimums, but the exact minimums depend on the published procedure.