How can DMA be enabled for the device /dev/hda?

How can DMA be enabled for the device /dev/hda?
A . echo "1" >/proc/ide/hda/dma
B . sysctl -w dev.ide.dma=1
C . dma add /dev/hda
D . hdparm -d 1 /dev/hda
E . insmod dma dev=/dev/hda

View Answer

Answer: D