If Democrats do not win the Senate according to the criteria here, this question will be N/A'd. If Democrats do win the Senate, each option for which Democrats won the Senate race will resolve YES, and all others will resolve NO. Winners of Senate races will be based on AP calls, and I will wait 48 hours after an AP call to ensure the call is not retracted.
Note that Dan Osborn winning the Nebraska race will count as Dems winning, regardless of whether or not Osborn ends up caucusing with the Democrats. I may bet on this market.