Query on minterms


Consider the logical functions given below.
If f is logic zero, then find the maximum number of possible minterms in function image


Ans is D. Since listen f is 0 because the intersection of minterms at f1,f2,f3 is 0. Since we can see that f1 and f2 both are containing 2,4 minterms so f3 can’t contain these and rest it can contain so it can have max 6 number of minterms


Here you can see in truth table, f3 can all values which f1.f2 doesn’t have in order to get all zeros at f
Hence at function f3 we have minterms (0,1,3,5,6,7)

I’ve spent 2 precious hours of my life to understand this question.