Which of the following best describes a hybrid cloud model?

a$.$ The cloud infrastructure is owned and operated by a third$-$party provider and is only available to a specific organization or group of users

b$.$ The cloud infrastructure is owned and operated by the customer

c$.$ The cloud infrastructure is owned and operated by a third$-$party provider and is available to the general public

d$.$ A combination of public and private cloud infrastructure, where some resources are shared and some are dedicated