For the expression f(x)=ax2+bx+c,(a>0), the condition for both real roots of f(x) to be greater than (or) lesser than a real value M is,
f(M)>0
As a>0, graph of f(x) is cup shaped parabola.
For M to be less than both roots (or) greater than both roots see that f(M)>0.
So, option A is true.