Where The Revenue Went

The dashboard total and the per-region breakdown disagree and nobody can find a filter that explains it.

region revenue
east 10.0
west 20.0
NaN 30.0
east NaN
NaN 50.0
print(df["revenue"].sum(), df.groupby("region")["revenue"].sum().sum())

What prints?

A

110.0 20.0

B

110.0 30.0

C

110.0 110.0

D

nan 30.0