To find the Jordan Canonical Form Consider a matrix A (5x5) with all entries = 1. Here the entries are considered as elements of $F_5$ ,the finite field of order 5. 
What is the Jordan canonical form?
I have found out that $A^2=0$ and thus the minimal polynomial is $x^2$.
So I know there are (two 2x2 blocks and one 1x1 block) OR (one 2x2 block and three 1x1 blocks)
How do I tell which?

Hint. Consider the rank of $A$.
