In Which One of the Following Examples Is Metacognition Most

In which one of the following examples is metacognition most clearly illustrated?

A) Erika knows all the letters of the alphabet before she begins kindergarten.
B) Tania knows how much of a book she is likely to remember a month later.
C) Ryan can read fourth grade books at the age of six.
D) Alex has a photographic memory that enables him to remember everything he sees.