Material can pass back and forth easily between the conscious level and the

a. unconscious level.

c. nonconscious level.

b. preconscious level.

d. all of the above.

Material can pass back and forth easily between the conscious level and the b) preconscious level.

Preconscious are thoughts which are unconscious at the particular moment in question, but which are not repressed and are therefore available for recall and easily "capable of becoming conscious" - such as tip of the tongue phenomenon and blindsight.