If `A = {5k +1 : k \in \mathbb{Z}}` and `B = { x : x \in \mathbb{Z}` and `x+4` is divisible by 5`}`, then which of the following is true?--
(a) `A \subset B`, (b) `B \subset A`, (c) `A = B`, (d) `A \cap B = \phi`