Let the given equations be 1,2,3,4 in the order they are given.
Adding equation 2 and 3 -
10a + 10b + 10c + 10d = 0; Let this be equation 5
Adding equation 1 and 4 -
6a + 10b + 10c + 6d = 0; Let this be equation 6
Equation 5 minus 6 :
we get : 4a + 4d =0
so (a+d) =0
if (a+d) =0 then (a+d)(b+c)=0
therefore answer is B