Chantal Knows She Went into the Bedroom for Some Reason

Chantal knows she went into the bedroom for some reason, but now that she is there, cannot remember what it is. She feels like she knows what it is, but just cannot retrieve the memory. This happened the other day when she was telling her sister about a problem with her refrigerator, but could not remember the word "refrigerator" to save her life! These experiences of knowing something without being able to retrieve it are examples of

A) anterograde amnesia.
B) disorientation.
C) delirium tremens.
D) the tip-of-the-tongue phenomenon.