let p(x)=x and q(x)=2x-1 these are two polynomials of degree 1 suppose n=4 so n/2=2 so d<n/2 both these polynomials are satisfying these relation of degree if we put different values p(1) will be same for both the polynomials but p(2), p(3),p(4) will be different for both the polynomials hence 3 different values 1 same value hence i can say that n-d that 4-1=3 differ values. Hence option d is the answer.