Although One May Believe That P, and P May Be

Although one may believe that p, and p may be true, one may still not know that p. This situation is universally agreed to arise from

A) the use of induction (i.e., one can never acquire a sufficiently numerous and varied data set) .
B) the use of abduction (i.e., one can never be sure one inferred the correct explanation) .
C) the use of a priori reasoning (i.e., one may not have considered the role of a posteriori reasoning) .
D) luck (i.e., one may not have been justified in believing p) .