When installing a HotFix on a BIG-IP device, F5 best practices require:

Installing the base TMOS image on a new, unused boot volume (HD1.2)

This ensures the upgrade happens on a clean volume.

The existing active boot location remains untouched for rollback.

Installing the HotFix onto the SAME new boot volume (HD1.2)

HotFixes must be applied on top of a base version.

They cannot be installed on an empty volume.

They must match the base image version.

Activating the new boot volume (HD1.2)

The system reboots into the updated software stack.

Activation happens after base + HotFix installation is complete.

This sequence is exactly shown in Option C :

Install base Image in HD1.2

Install HotFix in HD1.2

Activate HD1.2

Why the other options are incorrect:

A. Install HotFix before base image

Impossible.

HotFix requires an installed base version first.

B. Installing HotFix on HD1.1 (active boot volume)

Not recommended.

Upgrading in-place removes rollback safety.

HotFix cannot be applied cleanly without applying base image first.

D. Activate HD1.2 before installing anything

You cannot activate an empty boot volume.

Activation only occurs after the base + HotFix software is installed.