一道GMAT数学题,求高人指教.
Forafinitesequenceofnonzeronumbers,thenumberofvariationsinsignisdefinedasthenumberofpairsofconsecutivetermsofthesequenceforwhichtheproductofthetwoconsecutivetermsisnegative.Whatisthenumberofvariationsinsignforthesequence1,-3,2,5,-4,-6
(A)One
(B)Two
(C)Three
(D)Four
(E)Five