Our Relatively Stable Ability to See a Limit of About

Our relatively stable ability to see a limit of about 11 letters means that

A) our reading span is not limited just by how many letters can fit into the fovea of our retinas.
B) we only see letters to the right of the fixation letter and never any to the left.
C) we see letters much better than we see numbers.
D) letters which do not identify a word are "seen" most easily.