In which of the following situations would it be appropriate to install a hotfix?

In which of the following situations would it be appropriate to install a hotfix?

A.
A patch in a service pack fixes the issue, but too many extra patches are included.

B.
A patch is not available and workarounds do not correct the problem.

C.
A patch is available, but has not yet been tested in a production environment.

D.
A patch is too large to be distributed via a remote deployment tool.