Time left $0$:$09$:$09$

Which of the folllowings is not considered as a type of a system $?$

a$.$ Continuous and discrete systems

b$.$ Static and dynamic systems

c$.$ Permanent and temporary systems

d$.$ Natural and human$-$made systems

e$.$ Physical and virtual systems

f$.$ Open and closed systems

g$.$ Restricted and complex systems

h$.$ Deterministic and stochastic systems