What Do We Mean When We Say That Particles Such

What do we mean when we say that particles such as neutrinos or WIMPs are weakly interacting?

A) They interact with other matter only through the weak force and not through gravity or any other force.
B) They are only weakly bound by gravity, which means they can fly off and escape from galaxies quite easily.
C) The light that they emit is so weak that it is undetectable to our telescopes.
D) They respond to the weak force but not to the electromagnetic force, which means they cannot emit light.