Which three statements are true regarding Flex ASM on a…

A – This is correct!

Hub Nodes are similar to Oracle Grid Infrastructure nodes in an Oracle Clusterware standard Cluster configuration: they are tightly connected, and have direct access to shared storage. In an Oracle Flex Cluster configuration, shared storage can be provisioned to Leaf Nodes independent of the Oracle Grid Infrastructure.

B – This is wrong! Leaf node doesn’t have a ASM instance!

C – This is correct!

D – This is wrong! None database instance can run in a leaf node!

The cluster HUB nodes can be used to host cluster resources like in a pre 12c cluster (databases, ACFS, host VIPs, etc.). The cluster HUB nodes have the following characteristics:
 Look like pre 12c cluster nodes – shared storage is required
 There is a maximum of 64 nodes per cluster
 Anyway, node IDs are reserved for HUB nodes

The cluster LEAF nodes can be used to host applications, especially if we need to create dependencies between them and other existing cluster resources. The cluster LEAF nodes have the following characteristics:
 No shared storage necessary
 Connect to the cluster through the HUB nodes
 Separate VIPs for application can be created (additional network need to be manually created)
 The first LEAF node will have a node ID 100
 Currently no database instances can be started on a leaf node. However, Oracle creates a new default listener resource LISTENER_LEAF during the installation on the LEAF nodes which are not actively used in the current 12.1.0.2 version and seems to be reserved for future releases.

E – This is wrong!

Oracle Flex ASM clients with direct access to Oracle ASM disks

With this mode, database clients that are running on Hub nodes of the Oracle ASM cluster access Oracle ASM remotely for metadata, but perform block I/O operations directly to Oracle ASM disks.

F – This is right!

The Flex ASM architecture also changes the way ASM Dynamic Volume Manager (ADVM) and ASM Cluster File System (ACFS) communicate with an ASM instance. ADVM and ACFS local as well as remote clients no longer connect to an ASM instance directly, but always via a new ASM Proxy instance, which has been introduced in the 12c release 1 version as a new local resource (started automatically on all HUB nodes).

An Oracle ASM proxy instance is an Oracle instance running on a Hub node with a direct Oracle ASM client. Oracle Automatic Storage Management Cluster File System (Oracle ACFS) and Oracle ASM Dynamic Volume Manager (Oracle ADVM) are supported with an Oracle ASM proxy instance.

F is wrong .
refer to question 55 which states to mount acfs on leaf node