if a disk system has an average seek time of 30ns and rotation rate of 360RPM. each track of the disk has 512 sectors each of size 512 Bytes. what is the time taken to read 4 successive sectors,also compute the effective data transfer rate
a) 0.0843 sec , 1536 kbps
b) 0.123 sec , 1436 kbps
c) 0.156 sec ,1326 kbps
d) 0.135 sec , 1252 kbps