A hard disk of $20$ sectors per track and $400$ tracks per surface in $15$ double$-$sided platters disk, and platters rotates at a speed of $2400$ RPM with average seek time $30$ ms$.$ Each sector contains a block of size $512$ bytes and gap size between blocks $128$ bytes. What is the total capacity of the disk?

Select one:

a$.117\mathrm{.}18MB$

b$.146\mathrm{.}5MB$

c$.$ none

d$.61MB$

e$.76MB$