To find out quickly if multiplication will be positive or negative, count the number of negative signs in each equation. If it comes out even, it is positive. If odd, it will come out negative. Only exception is when 0 is in the mix. First equation has 2, therefore is positive because even. Second has 4, which is another positive because even. 3rd is 5, which is negative because it is odd and has NO 0. 4th has 0.
C is the answer and I hope this helped.
