What grade do you need to unlock the next mission?

[Snowman]

Finished post office with a C but it did not move on, is B the passing requirement or is it a glitch?

[Qored]

c+ if it is the same as the achievements

[Rudie5735]

I've had a D grade, after near perfect run on relapse only for a civi with possible suspect character model kick down a door and dash towards me (he ate 4 rounds of 7.62NATO..., -500pts + no 500pts granted for saving civilians). That counted as pass and I can launch hide and seek. I think D is the bare minimum.