Rain, and the consequent sharing of points between Bangladesh and the West Indies, has completely altered the Pool B scenario.
If there is no further rain, here's how things could turn out for each team:
South Africa: Till yesterday, they badly wanted a West Indies win over Sri Lanka. Now they would probably like just the opposite! And the best news is that, whatever the outcome of the West Indies-Sri Lanka match, South Africa stay in the reckoning till March 3, when they play Sri Lanka (a Sri Lanka win over the West Indies will now not automatically eliminate South Africa).
If Sri Lanka defeat the West Indies then we might end up with Sri Lanka:20, South Africa:12, New Zealand:16 and West Indies:14 just before the Sri Lanka-South Africa match on March 3. If South Africa win that match (which they must!), then the West Indies remain stranded at 14 and South Africa, Sri Lanka and New Zealand go through, each carrying four points with them, to the Super Six.
If the West Indies defeat Sri Lanka then they would be expected to reach 18 and qualify for the Super Six. Then, if South Africa beat Sri Lanka, it might be between South Africa, New Zealand and Sri Lanka, each tied at 16 points. This scenario is also sufficiently promising since South Africa should feel confident of maintaining a high net run rate. South Africa would like New Zealand to go out so that they advance with 4 points into the Super Six (gained from Sri Lanka). If Sri Lanka go out then South Africa make it, but with 0 points.
West Indies: They simply must defeat Sri Lanka! If they do, then they can get greedy and hope (a) that South Africa defeat Sri Lanka and (b) that New Zealand go out! Then the West Indies go up with 8 points (gained by defeating Sri Lanka and South Africa). If the West Indies don't defeat Sri Lanka, they can only hope that Sri Lanka defeat South Africa so that South Africa are stranded at 12 points. This is a bad scenario for the West Indies even then because they will go up with 0 points.
Sri Lanka: They are the current king makers in the Group. They would like to defeat both the West Indies and South Africa so that they go up unbeaten and with 8 full points. If they lose to South Africa, and South Africa advance to the Super Six, Sri Lanka could advance with only 4 points. In the worst case scenario, where they lose to both the West Indies and South Africa, they might either be eliminated (if New Zealand and South Africa both have better NRR's) or go up with 0 points (assuming that New Zealand have the lowest NRR and are therefore eliminated) and Sri Lanaka go up with South Africa and the West Indies.
New Zealand: They could still do the smart thing and go to Kenya to guarantee themselves a Super Six berth. Better still, they will get at least 4 points as they go up (they have defeated both South Africa and the West Indies and at least one of the two must qualify!). By playing and defeating Kenya, they could even advance with 8 full points if both South Africa and the West Indies defeat Sri Lanka (in that case, New Zealand have 20, the West Indies have 18, Sri Lanka and South Africa have 16, but South Africa go through because of their win).
If they don't go to Kenya, New Zealand would like Sri Lanka to defeat West Indies so that they advance to the Super Six with 4 points. If the West Indies defeat Sri Lanka, New Zealand would feel a little jittery; their NRR at the moment isn't great. But there could also be a pot of gold in this quagmire if Sri Lanka are eliminated by the NRR; then New Zealand will join South Africa and the West Indies into the Super Six -- and carry 8 full points!
