Correct option (A) Positive
ax2 + bx + c = 0 has imaginary roots. That is b2 - 4ac <0
The discriminate of the equation f(x) = a2x2 + abx + ac is
D = a2b2 - 4a2ac = a2(b2 - 4ac) < 0
The coefficient of x2 in quadratic equation is (a2 > 0) positive. That is, a2x2 + abx + ac > 0.