For a finite sequence of non zero numbers, the number of variations in the sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What is the number of variations in sign for the sequence 1,-3,2,5,-4,-6?

1)1

2)2

3)3

4)4

5)5

i remember when i did this problem for the first time, i re-arranged them in ascending order and got the wrong answer. what part of the question should stop me from doing such mistakes?