Mapreduce task io sort mb

You observed that the number of spilled records from Map tasks far exceeds the number of map
output records. Your child heap size is 1GB and your io.sort.mb value is set to 1000MB. How
would you tune your io.sort.mb value to achieve maximum memory to disk I/O ratio?

Mapreduce task io sort mb

A.
For a 1GB child heap size an io.sort.mb of 128 MB will always maximize memory to disk I/O

B.
Increase the io.sort.mb to 1GB

C.
Decrease the io.sort.mb value to 0

D.
Tune the io.sort.mb value until you observe that the number of spilled records equals (or is as
close to equals) the number of map output records.