For a compression or heating process what is the expression for effectiveness $\varepsilon$?
(a) $\varepsilon =\frac{Increase of availability of the surroundings}{Loss of availity of the system}$
(b) $\varepsilon =\frac{Increase of availability of the surroundings}{Loss of availity of the surroundings}$
(c) $\varepsilon =\frac{Loss of availity of the surroundings}{Increase of availability of the system}$
(d)$\varepsilon =\frac{Loss of availity of the system}{Increase of availability of the surroundings}$