Four basic types of $Al$ agents that embody the principles underlying almost all intell$[$gent systems are:

a$)$ software agents, hardware agents, utility$-$based agents and simple reflex agents

b$)$ software agents, model$-$based reflex agents, utility$-$based agents and simple reflex agents

c$)$ software agents, hardware agents, goal based agents and simple reflex agents

d$)$ model$-$based reflex agents,, hardware agents, utility$-$based agents and simple reflex agents

e$)$ model$-$based reflex agents,, goal based agents, utility$-$based agents and simple reflex agents