Arrhenius Equation

A(g) + B(g)  C(g)

The rate law for the above reaction is:

-d[A]/dt = k[A][B]

The rate constant is 2.97×10^-6 L mol^-1 s^-1 at 347.0°C and 5.23×10^-5 L mol^-1 s^-1 at 555.0°C.

Use the Arrhenius equation

k = Ae^-E_a^/RT

to:

part A :-Calculate E_a for this reaction.?

5.89×10¹ kJ/mol  (i GOT THIS PART CORRECT)

PART B:- Calculate the rate constant k at 423.0°C for this reaction.?

PART C:-Calculate the pre-exponential factor A for this reaction.?

HOW TO SOLVE PART B (I GOT THE ANSWER 3.32*10^-6 BUT IT IS INCORRECT, I USED THE UNITS L/mol/s) and how to solve part C?