Given: $32$ bit address space

$2.$a$.(0\mathrm{.}5$ pts$)$ How many memory locations can be addressed with a $32$ bit address bus? You may answer in hex$/$decimal$/$a power of two.

$2.$b$.(0\mathrm{.}5$ pts$)$ If each process is allowed up to $16$ MB of physical memory, how many processes can run on this machine?

$2.$c$.(0\mathrm{.}5$ pts$)$ If the data bus is $8$ bits, how many memory accesses are required to read $16$ MB of memory?

$2.$d$.(0\mathrm{.}5$ pts$)$ If the data bus size is increased to $32$ bits, $,$ how many memory accesses are required to read $16$ MB of memory?