Select all the definitions below that describe shadow$-$IT$.$

a$.$ IT is used for work tasks outside of IT policies, rules, guidelines, standards, and procedures.

b$.$ IT$-$related expenses in organizations for anything other than the IT provided by the enterprise.

c$.$ Solutions that grew out of End User Computing tools and applications adapted for other purposes and had drifted out of IT's control.

d$.$ The autonomous development, purchase, implementation, and use of various technology by departments other than IT$.$

e$.$ The business' use of hardware, software, systems, solutions, or services for work without the explicit approval or knowledge of IT$.$

f$.$ none of the above