Which KPI trend MDX expression should you use?

You need to define the trend calculation for the sales performance KPI.
Which KPI trend MDX expression should you use?

A.
IIF([Sales Variance %] > ([Sales Variance %], [Date].[Calendar].PrevMember), 0, 1)

B.
IIF([Sales Variance %] > ([Sales Variance %], [Date].[Calendar].PrevMember), 1, 0)

C.
CASEWHEN [Sales Variance %] > ([Sales Variance %], [Date].[Calendar].PrevMember) THEN -1 WHEN
[Sales Variance %] = ([Sales Variance %], [Date].[Calendar].PrevMember) THEN 0 ELSE 1 END

D.
CASEWHEN [Sales Variance %] > ([Sales Variance %], [Date].[Calendar].PrevMember) THEN 1WHEN
[Sales Variance %] = ([Sales Variance %], [Date].[Calendar].PrevMember) THEN 0 ELSE -1 END