Posner, Snyder, and Davidson's research showed that, if a visual stimulus occurs where we

do not expect it to occur,

a. we are unable to detect it at all.
b. we are able to detect it as quickly as we would if it appeared where we expected it to.
c. we are able to detect it more quickly than we would if it appeared where we expected it to.
d. we are slower to detect it than we would be if it appeared where we expected it to.
e. we are able to detect it immediately.

d. we are slower to detect it than we would be if it appeared where we expected it to.