What does it mean to say that a theory is "falsifiable"?

(a) Research has contradicted the theory.

(b) We can imagine results that would contradict the theory.

(c) Most people disagree with the theory.

(d) People are still debating whether the theory is correct.

Falsifiable is a theory that is false and where it is contradicted by researcher and there is evidence to prove. Like example, Freud's theory on levels of mind conscious, unconscious and unconscious is falsifiable because it is hard to prove and measure subconscious and conscious mind.