According to Oracle.com documents or resources, the four actions that you should take before proceeding with applying updates to your Exadata Database Machine are:
1. Consult My Oracle Support note 888828.1 to determine the current recommended Exadata software release123.
2. Check the Exadata Critical Issues My Oracle Support note 1270094.1 for any issues not added to the latest version of exachk453.
3. Run exachk and resolve only WARNINGS that you have not seen before3.
4. Run the appropriate patchmgr preqequisite check step for each component being updated3.

For database servers, perform a server backup using patchmgr -dbnodes dblistfile -backup -rolling. This is according to the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book . The other statement is false as exachk should not be used to resolve warnings or errors [1], but rather to identify them so that they can be addressed. Additionally, patchmgr should not be used with the --autofix, --autobackup, --upgrade, or --rolling flags as this could cause unexpected issues.

According to Oracle's documentation12, some of the statements that are true about applying updates on Exadata systems are:
Failed storage server updates are automatically rolled back to a previous release1.
When running a "yum update" for a new Exadata release, all other repositories should be disabled1.

According to the Oracle Exadata Database Machine Technical Architecture1, the initial storage configuration after the standard (non-virtualized) deployment of a new Exadata Database Machine with High Capacity storage servers includes two ASM disk groups: DATA_<DBM_Name> and RECO_<DBM_NAME>. These disk groups are built on hard disks and flash disks inside the Exadata Storage Servers1.
The correct statements about this configuration are:
Option D: There is free space available on flashdisks inside the Exadata storage servers for possible use for storage indexes. Storage indexes are a feature of Exadata Storage Software that can improve query performance by avoiding unnecessary I/O operations. Storage indexes use a small amount of flash memory to store metadata about data blocks stored on disk1.
Option E: There is free space available on flashdisks inside the Exadata storage servers to configure Exadata Smart Flash Logs. Exadata Smart Flash Logs are another feature of Exadata Storage Software that can improve database performance by using flash memory as an extension of the database redo log buffer. This can reduce latency and increase throughput for redo log writes1.

The two actions that are not appropriate for monitoring how a large production table is accessed in order to leverage the benefits of the Exadata Platform are A) querying VSSYSTEMEVENTS and filtering for the event 'cell physical IO interconnect bytes returned by smart scan', associated to your table; and B) querying v$segmentstatistics and filtering for the Object ID of your table from dbaobjects and the the column STATISTICNAME='optimized physical reads'. Instead, you should query v$SYSTAT and filter for the statistic 'cell smart table scan', associated to your table (C), or run the CellCli-command list activerequest, filtering for the attributes ioReason and objectNumber, that you specify as 'Smart Scan' and the Object ID of your table from DBA_OBJECTS (D). These two methods are outlined in the Oracle Exadata Database Machine X9M Implementation Essentials Official Text Book (Chapter 8, Monitoring the Exadata Database Machine).