How many address bits the following memories do require?

a$.2$ MBytes memory

Answer: This requires $2\mathrm{.}4$ address bits

b$.32$ Kbits memory

Answer: This requires $1\mathrm{.}5$ address bits

c$.64$ Mbits memory

Answer: This requires $2\mathrm{.}6$ address bits

d$.2$ GBytes memory

Answer: This requires $3\mathrm{.}4$ address bits