IFR Questions

[Condorito]

Hi guys/girls. I have a few questions regarding IFR (General Aviation)

1) For an Approach Ban, if an airport has for a given runway RVR A and RVR B, do BOTH have to be serviceable in order for the Approach Ban to be in effect? If one is unserviceable, does that cancel the Ban?

2) If RVR A is 1200+ but RVR B is less than 600? Do they both have to be at or above minimums or is one enough? What about the other way around (RVR A less than 1200 and RVR B more than 600)?

3) For Take-off, is RVR A the only one that counts?

4) For RVO if RVR A is U/S and RVR B is above minimums, can you conduct an approach? Again, one being U/S

Thank you for taking your time to help me out! Highly appreciate it.