What is the root cause of this alert?

One of your systems show the internal Disk Full (Alert 30) alert.

What is the root cause of this alert?
A . Reading from the /hana/log/<sid> volume is NOT possible
B . Writing to the /hana/data/<sid> volume is NOT possible
C . Runing out of free space on the /hana/shared volume
D . Exceeding system quota on the /usr/sap volume

Answer: C