An administrator is performing upgrades to ESX 4. 0 from exist 3.x and ESX 2. x hosts. Which of the following is true about this procedure?

A.
A direct, in-place upgrade can be performed only on ESX 3. 0 and later Hosts

B.
A direct, in-place upgrade can be performed only on ESX 2. 5 and later Hosts

C.
A direct, in-place upgrade can be performed only on ESX 3. 5 and later Hosts

D.
ESX 3.x and later Hosts can be upgradeD. but the upgrade cannot be performed in-place

Explanation:
Direct, in-place upgrade from ESX 2.5.5 to ESX 4.0 is not supported, even if you
upgrade to ESX 3.x as an intermediary step. The default ESX 2.5.5 installation creates a
/boot partition that is too small to enable upgrades to ESX 4.0. As an exception, if you
have a non-default ESX 2.5.5 installation on which at least 100MB of space is available
on the /boot partition, you can upgrade ESX 2.5.5 to ESX 3.x and then to ESX 4.0.