This looks like homework. Please always mention the own effort to make sage compute something on the way. Here, a possibility to proceed - for each field - would be to construct the corresponding field, the ring of polynomials over it, then define $p$ over this field, finally ask for the factorization. For instance:

sage: F = GF(5)
sage: F.<x> = PolynomialRing( F )    # or F[] for short, but criptic.
sage: factor( x^3 - 3*x + 4 )
x^3 + 2*x + 4

Which is the code for the other two fields? (Of course, we can already decide...)