The correct option is B true solution
A true solution is a homogeneous mixture of two or more substances with a particle size of less than 10−9m or 1 nm dissolved in the solvent.
A suspension is a heterogeneous mixture in which particles down mixture upon standing, with particle size being over 1000 nm.
A colloid is a heterogeneous mixture in which the dispersed particles are intermediate in size between those of a true solution and suspension i.e (1−1000 nm).